I tend to buy used G scale stuff, because my railroad is on a shoestring budget. A couple months back I bought a couple of Piko shops that were badly in need of repair. One thing they needed was new windows. The old plastic was brittle and opaque, so I thought about casting new panes and using acrylic for the glass. But getting a good casting for something so fine turned out to be harder than I thought. So I decided to laser cut a set.