[leftthegan] found an IKEA Kallax 4×4 shelving unit for a fair price, and after a few design iterations — some due to the aforementioned regulations — it was modified by adding a shelf ...

There are dozens of brilliant KALLAX DIYs that prove it's the most versatile piece sold at IKEA ... simple assembly also gets high marks. At just $25, it's among the least expensive bookshelf ...