Tube rack multi-size

Tube rack to accommodate 50 mL falcons, 15 mL falcons, 1.5 mL, and 0.5 mL Eppendorf tubes.

The smallest holes fit 0.5 mL Eppendorf tubes, but can also fit 1.5 mL Eppendorf tubes (which can be nice when you want to pipette from them and be able to see the liquid inside without picking it up). Pictures correspond to a print of v5 with black tough PLA and PVA support (already dissolved in water). 

Current thoughts: For the next version I will make more 1.5 mL holes, a little bit smaller (<10%), and I will add more space for falcon tubes in the flat face, as it is nice to have space for all tube types in the same face.