I'd like to know this too, there doesn't seem to be any easy explanation of what to do with that tri-point symbol, but I guess it's something pretty easy once you understand the mechanic like the coloured tetris like shapes.
Anyone had any luck finding unicode symbols for some of these shapes and icons too?
I accidentally solved the puzzle in the picture and I have no idea how it worked.Stuck on the next one now of course.
Edit: Think I've figured it out? Thanks for the hints guys.