Enter the size of the grid (an integer, see below) and wait for completion. Any grid size bigger than 15 can be done without too much hassle on Scratch. 15 - 10 can last a while. Below 10, please use : https://sulfurous.aau.at/html/app.html?id=263411694&turbo=true&full-screen=true&aspect-x=4&aspect-y=3&resolution-x=&resolution-y=
Had to create a new project because I couldn't save changes on the former one. Now shows the edges used, the grid and the points that are going to be used. Basically https://scratch.mit.edu/projects/246475360/ but with triangulation points chosen by applying edge detection on a grid whose size is given at the start by the user). The thumbnail used grid size 10. Uses https://scratch.mit.edu/projects/227722208/ in conjonction with @TheLogFather 's triangle filler.
