I have a two-year old daughter who loves playing with blocks and other construction toys. However, all of the block sets we've gotten her have either been too small for her to manipulate, require too much force to put together/take apart, and/or don't come in sufficient diversity of shapes. I've been teaching my daughter about 3d Printing (she loves being able to ask for a toy and watch it print), so I decided to see if we could design a better snap-fit block for toddlers. I'll do the design and she'll be my beta-tester. I've build openscad program so that the blocks can be made with any number of rows/columns. Version 1: 5 sided rectangular solid with a raised cylinder to fit into the open side Wall thickness - 2 mm Edge - 25.4 mm Height - 1.25 * edge Cylinder_radius - edge/2-wall-0.1 (exact fit less 0.1 mm)Version 2: 5 sided rectangular solid with a raised cylinder to fit into the open side Wall thickness - 1 mm Edge - 25.4 mm Height - 1.25 edge Cylinder_radius - edge/2-wall-0.1 (exact fit less 0.1 mm) Bevel - 0.85 cylinder_radiusI printed on a Replicator 2, sliced using Makerware using MiracleGrue, medium quality, with supports. The part was oriented with the raised cylinder pointing towards the build platform for easier support removal.