I read this everyday, several times (one of the perks of being in a diverse environment). It took me a few days to notice. The user interface design (mechanical) is not great, and the instructions on how to use the machine (typed below in plain text) are downright inconsistent.
Today's stair number: 1
The instructions read:
1. No coins necessary.
2. Turn knob slowly to extreme right until product vends.
3. If coins are not accepted, machine is empty.
DO NOT FORCE KNOB TO TURN.
Call matron or custodian.