Sort:  

Spot on. Try to evenly push the edges in towards the centre to make it invert. If you find it undoing when you handle it try what @ivan-g has done with creating little triangles. I love the paper choice.

Thank you :) I tried with the @ivan-g's triangles. Looks much neater :)

Coin Marketplace

STEEM 0.15
TRX 0.12
JST 0.026
BTC 56443.25
ETH 2493.88
USDT 1.00
SBD 2.23