Coin and small items interlocking holder

A friend of mine asked me if I could make a holder to have the coins under his cash register, so I made these interlocking boxes that can be used also to organise the desk!
They have two male and two female locks so they can be connected in many ways!
Each compartment is 8cm x 8cm x 4cm and has a small slope in one side so it is easier to remove any item from inside!

I used .3mm layer height and found that it is best to have 7 to 10% infill!