Because my home server should look like a home.

The power USB cable goes trough the chimney, the HDMI and audio connectors are blocked (because it's a headless server box) but can be still used if you take the roof off, the network and USB connectors are fully exposed on the back and there's a slot for the SD card on the front.

There's space inside for a Raspberry PI 2 or 3 Model B and a 40mm fan.

To assemble slide the Raspberry Pi (without an SD card) into the slot in the "house" part, then put the "top" part on, well, the top of the Raspberry to hold it in place.

Insert the micro USB part of the power cable trough the chimney and push the "roof" part into place.

Print the "house" and "top" parts with no support, infill doesn't matter.

Print the "roof" part with supports and high infill, it requires a lot of support (sorry) be careful not to break any of the 4 legs when you take the supports off