There's an achievment where you need to produce 'the old level 17 shape'
What is that shape?
It is quite hard, 3 layers (RgWrRgWr:CwCrCwCr:SgSgSgSg) try rotating layers tho, i can't remember the shape 100%
Edit: I just realized it is the shape in processing upgrade tier 5
It's actually WrRgWrRg:CwCrCwCr:SgSgSgSg
I made this shape for an upgrade: WrRgWrRg:CwCrCwCr:SgSgSgSg and got the achievment
What do you think?