It's perfect, very easy and simple but when you building up looks very sophisticated:))))
Pattern: (I used several colors) Using one of your color , ch 4. Join with sl st to form a ring.
Round 1: Ch 2 (counts as first dc throughout pattern), work 11 dc in ring (12 dc). Join with sl st in top of ch2 from beginning (join in this manner throughout pattern).
Round 2: Ch 2, dc in same st, 2 dc in each dc around (24 dc). Join.
Round 3: Ch 2, *skip next dc, work (dc, ch 2, dc) in next dc. Repeat from * around, ending with dc in base of beginning stitch, ch 2, join with sl st in top of ch2 from beginning.
Round 4: Sl st into ch 2 space, work (ch 2, dc, ch 2, 2 dc) in ch 2 space, * work large shell in next ch 2 space, repeat from * around. Join.
Round 5: Sl st into next st, ch 2, * work large shell in ch 2 space, dc in next dc, skip next 2 dc, dc in next st. Repeat from * around. Join.
Round 6: Sl st into next st, ch 2, dc in next st, * work large shell in ch 2 space, dc in each of next 2 dc, skip the next 2 sts, dc in each of next 2 dc. Repeat from * around, ending with skip 2 sts. Join, cut yarn.
Round 7: Using second color , sl st into next st, ch 2, dc in next 2 sts, * work small shell in next ch 2 space, dc in next 3 sts, skip 2 sts, dc in next 3 sts. Repeat from * around, ending with skip 2 sts. Join, cut yarn.
Round 8: Using different color , sl st into next st, ch 2, dc in next 2 sts, * work large shell in ch 2 space, dc in next 3 sts, skip next 2 sts, dc in the next 3 sts. Repeat from * around, ending with skip 2 sts. Join.
Round 9: Sl st into next st, ch 2, dc in next 3 sts, * work large shell in ch 2 space, dc in next 4 sts, skip next 2 sts, dc in next 4 sts. Repeat from * around, ending with skip 2 sts. Join.
Round 10: Sl st into next st, ch 2, dc in next 4 sts, * work small shell in ch 2 space, dc in next 5 sts, skip next 2 sts, dc in next 5 sts. Repeat from * around, ending with skip 2 sts. Join.
Round 11: Sl st into next st, ch 2, dc in next 4 sts, * work large shell in ch 2 space, dc in next 5 sts, skip next 2 sts, dc in next 5 sts. Repeat from * around, ending with skip 2 sts. Join.
Round 12: Sl st into next st, ch 2, dc in next 5 sts, * work large shell in ch 2 space, dc in next 6 sts, skip next 2 sts, dc in next 6 sts. Repeat from * around, ending with skip 2 sts. Join, cut yarn.
Round 13: Using color different, sl st into next st, ch 2, dc in next 6 sts, *work small shell in ch 2 space, dc in next 7 sts, skip next 2 sts, dc in next 7 sts. Repeat from * around, ending with skip 2 sts. Join, cut yarn.
Continue working in rounds in pattern as established,
always working 1 round with small shells followed by 2 rounds with large shells. You will work 5 rounds of each color, 1 round of white (always a small shell round), 5 rounds of next color, 1 round of white, and so on. Continue repeating rounds 8-13 with the number of dc increasing in each large shell round between the "ch 2 space" and the "skip 2 sts" until the last round of rainbow colors is worked. Join, cut yarn.
Final round: I made picot edge- 4sc, picot, 4sc, picot... at the corners 3 picots.