Hello Pipioluu!!!
Last art class, was abaut maths (HORROR!!!) abaut impossible figures, it strange figures have a trick to do:
(Escher two)
-All the lines have to be 30º. It's more easy that you think. We have right triangle and a set square:
(Right triangle) (Set square)
How to make paralel lines
It's in catalan but I'm going to translate:
1. Fit the right triangle to the top.
2. Put the set square next to the right triangle, like in the photography.
3. Grab the right triangle and muve up or down the set square
Good week
Sunni