BlocksCAD - Drag & Drop Visual Coding on the Browser

If you want to teach your 8+ aged kids (or teach yourself) the basics of Parametric Thinking, this is easiest block programming tool. You simply drag and drop code blocks available from a huge library of blocks to create 3D objects. You can snap together code blocks to form group of commands. You can then adjust the values in the blocks and see your model recreate itself.