Tetrominos

I came across another tetris parts collection, and I wanted to have one in OpenSCAD to be able to tweak it - especially allow for a hole in the back for inserting a magnet for these pieces to be used on fridges or other particularly fitting places. This is work in progress and will probably never be 'finished', as everything else. It quite probably contains a few bugs too. Feel free to enjoy - I may even upload it to github some day