Limited Oasis Island decorations

Event-only Oasis Island decorations with their bonuses, release dates and level tables.

Overview

Limited decorations come from events rather than the Island Shop. Most give a squad-wide bonus, and like other decorations each needs duplicate Lv. 1 copies to upgrade. Some can also be made from Mythic General Decoration Components, which the Island Shop sells from Fountain of Life Lv. 10.

Decorations

Decoration	Rarity	Size	Bonus at Lv. 1	Max level	Bonus at max level	Listed from	Components
Court of Knowledge	Mythic	3 × 3	Squads' Attack 1%	20	Squads' Attack 20%	—	Yes
Horn of Victory	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	—	No
Lion of Glory	Mythic	3 × 3	Squads' Attack 1.5%	10	Squads' Attack 15%	—	No
Merchant Caravan	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	—	Yes
Ritual Altar	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	—	Yes
Small Coliseum	Epic	3 × 3	Squads' Defence 0.5%	5	Squads' Defence 2.5%	—	No
Grizzly Statue	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	8 Jul 2025	Yes
Cheesy Perfection	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	21 Aug 2025	Yes
Lantern Garden	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	2 Oct 2025	Yes
Wicked Hut	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	29 Oct 2025	Yes
Autumn Canvas	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	25 Nov 2025	Yes
Treasure Icicle	Epic	3 × 3	Squads' Attack 0.5%	5	Squads' Attack 2.5%	24 Dec 2025	No
Winter Rollercoaster	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	25 Dec 2025	Yes
New Year Greeting	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	31 Dec 2025	Yes
Journey of the Heart	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	10 Feb 2026	Yes
Jade Jubilation	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	17 Feb 2026	Yes
Dragon Sculpture	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	9 Mar 2026	No
Sleeping Drakethrone	Mythic	3 × 3	Squads' Attack 2%, Squads' Defence 2%, Squads' Lethality 2%, Squads' Health 2%	10	Squads' Attack 20%, Squads' Defence 20%, Squads' Lethality 20%, Squads' Health 20%	9 Mar 2026	No
Starstation	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	19 Mar 2026	Yes
Eggchanted	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	1 Apr 2026	Yes
Lakeside Dream	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	30 Apr 2026	Yes
Dinosaur Fossils	Epic	3 × 3	Training Speed 3%	5	Training Speed 15%	27 May 2026	No
Dinosaur Fort	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	28 May 2026	Yes
Goddess of Glory	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	10 Jul 2026	No
Passing of the Sword	Mythic	3 × 3	Squads' Attack 1%, Squads' Defence 1%	10	Squads' Attack 10%, Squads' Defence 10%	10 Jul 2026	No
Pro Ball Trainer	Mythic	3 × 3	Squads' Defence 1%	10	Squads' Defence 10%	11 Jul 2026	Yes
Mini Crucible	Mythic	3 × 3	Squads' Attack 1%	10	Squads' Attack 10%	6 Aug 2026	Yes
Dream Sailing	Mythic	4 × 4	Squads' Attack 1%	10	Squads' Attack 10%	22 Sept 2026	Yes

Level tables

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 20 takes 433 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58
11	Squads' Attack 11%	11,000	15	73
12	Squads' Attack 12%	12,000	20	93
13	Squads' Attack 13%	13,000	25	118
14	Squads' Attack 14%	14,000	30	148
15	Squads' Attack 15%	15,000	35	183
16	Squads' Attack 16%	16,000	40	223
17	Squads' Attack 17%	17,000	45	268
18	Squads' Attack 18%	18,000	50	318
19	Squads' Attack 19%	19,000	55	373
20	Squads' Attack 20%	20,000	60	433

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1.5%	1,000	—	1
2	Squads' Attack 3%	2,000	2	3
3	Squads' Attack 4.5%	3,000	3	6
4	Squads' Attack 6%	4,000	4	10
5	Squads' Attack 7.5%	5,000	5	15
6	Squads' Attack 9%	6,000	6	21
7	Squads' Attack 10.5%	7,000	7	28
8	Squads' Attack 12%	8,000	8	36
9	Squads' Attack 13.5%	9,000	10	46
10	Squads' Attack 15%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Epic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 5 takes 15 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 0.5%	500	—	1
2	Squads' Attack 1%	1,000	2	3
3	Squads' Attack 1.5%	1,500	3	6
4	Squads' Attack 2%	2,000	4	10
5	Squads' Attack 2.5%	2,500	5	15

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 4 × 4 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%	1,000	—	1
2	Squads' Attack 2%	2,000	2	3
3	Squads' Attack 3%	3,000	3	6
4	Squads' Attack 4%	4,000	4	10
5	Squads' Attack 5%	5,000	5	15
6	Squads' Attack 6%	6,000	6	21
7	Squads' Attack 7%	7,000	7	28
8	Squads' Attack 8%	8,000	8	36
9	Squads' Attack 9%	9,000	10	46
10	Squads' Attack 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Epic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 5 takes 15 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 0.5%	500	—	1
2	Squads' Defence 1%	1,000	2	3
3	Squads' Defence 1.5%	1,500	3	6
4	Squads' Defence 2%	2,000	4	10
5	Squads' Defence 2.5%	2,500	5	15

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Defence 1%	1,000	—	1
2	Squads' Defence 2%	2,000	2	3
3	Squads' Defence 3%	3,000	3	6
4	Squads' Defence 4%	4,000	4	10
5	Squads' Defence 5%	5,000	5	15
6	Squads' Defence 6%	6,000	6	21
7	Squads' Defence 7%	7,000	7	28
8	Squads' Defence 8%	8,000	8	36
9	Squads' Defence 9%	9,000	10	46
10	Squads' Defence 10%	10,000	12	58

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 10 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 2%, Squads' Defence 2%, Squads' Lethality 2%, Squads' Health 2%	5,000	—	1
2	Squads' Attack 4%, Squads' Defence 4%, Squads' Lethality 4%, Squads' Health 4%	10,000	1	2
3	Squads' Attack 6%, Squads' Defence 6%, Squads' Lethality 6%, Squads' Health 6%	15,000	1	3
4	Squads' Attack 8%, Squads' Defence 8%, Squads' Lethality 8%, Squads' Health 8%	20,000	1	4
5	Squads' Attack 10%, Squads' Defence 10%, Squads' Lethality 10%, Squads' Health 10%	25,000	1	5
6	Squads' Attack 12%, Squads' Defence 12%, Squads' Lethality 12%, Squads' Health 12%	30,000	1	6
7	Squads' Attack 14%, Squads' Defence 14%, Squads' Lethality 14%, Squads' Health 14%	35,000	1	7
8	Squads' Attack 16%, Squads' Defence 16%, Squads' Lethality 16%, Squads' Health 16%	40,000	1	8
9	Squads' Attack 18%, Squads' Defence 18%, Squads' Lethality 18%, Squads' Health 18%	45,000	1	9
10	Squads' Attack 20%, Squads' Defence 20%, Squads' Lethality 20%, Squads' Health 20%	50,000	1	10

Mythic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 10 takes 58 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Squads' Attack 1%, Squads' Defence 1%	1,000	—	1
2	Squads' Attack 2%, Squads' Defence 2%	2,000	2	3
3	Squads' Attack 3%, Squads' Defence 3%	3,000	3	6
4	Squads' Attack 4%, Squads' Defence 4%	4,000	4	10
5	Squads' Attack 5%, Squads' Defence 5%	5,000	5	15
6	Squads' Attack 6%, Squads' Defence 6%	6,000	6	21
7	Squads' Attack 7%, Squads' Defence 7%	7,000	7	28
8	Squads' Attack 8%, Squads' Defence 8%	8,000	8	36
9	Squads' Attack 9%, Squads' Defence 9%	9,000	10	46
10	Squads' Attack 10%, Squads' Defence 10%	10,000	12	58

Epic, 3 × 3 tiles, Type Limit 1. Reaching Lv. 5 takes 15 Lv. 1 copies in total.

Level	Bonus	Prosperity	Lv. 1 copies used	Total copies
1	Training Speed 3%	500	—	1
2	Training Speed 6%	1,000	2	3
3	Training Speed 9%	1,500	3	6
4	Training Speed 12%	2,000	4	10
5	Training Speed 15%	2,500	5	15

How decorations count

Decorations only count once they are placed on the island.
Each decoration has a Type Limit: only that many placed copies of it count, highest level first. A Type Limit of 0 means it gives no bonus or Prosperity.
Only the current level’s bonus counts, once for each copy within the Type Limit.
Upgrading uses unplaced Lv. 1 copies from the Island Storehouse. Dismantling an upgraded decoration returns the Lv. 1 copies used.