1.5 / 2 ml microcentrifuge tube holder (single)

Here is a simple holder for a 1.5 ml or 2 ml microcentrifuge (‘Eppendorf’) tube, as part of my 3d printing labware range. The goal was to make items which:
- Are functional (in this case securely holding tubes upright)
- Use minimal plastic, and so are quick/cheap to make
- Require little to no supports
- Take up as little bench space as possible
- Can be easily tweaked and combined to make whatever related custom labware is desired