My daughter stores most of her toys and creative stuff in an Ikea Billy bookcase, which is quite a mess to look at. I hence decided to build simple open storage boxes that can hold these items and make the closet look neat and tidy.
The boxes are made out of 3.6mm (approx. 1/8″) thick plywood. I made them 36cm wide, 24cm deep, and 26cm tall. Two will fit on one shelf, and you can make six of them out of a full sheet of plywood since all four sides just fit within the 122cm width of a plywood sheet. This also means that it is very easy to get all sides to be the same height, as a single cross-cut is done for all four.
The next step is a 45 degree mitre cut that will be at the bottom of the sides. Each side part also requires two more bevel cuts, on the edges where they meet the other side parts. Make sure you get the orientation right. Finally, the 36x24cm bottom also needs four mitre cuts.
For the grip, I designed and 3D printed a simple router template. Mark the centre of one of the long sides on the top, align the template, clamp it down and route the hole. I also designed and printed simple brackets that hold the sides rectangular during glueing. I first glue the sides together, then add the bottom. After the glue has set, a bit of sanding to round off the edges is all it takes to finish the boxes.