A simple three part 'Wheel of Fortune' type thing to remind me that I have taken my medications.
Take my pills, move the wheel round (attached very near pills) to the timeslot I have just used and shut the door till next pill time. 
Did I have my last medications of the day? .. I can check now.

Nothing special, you can print the 'wheel' part in two colours with a colour change/pause or if you have it, using multi colour printers.It prints easy and fast.To build, push the wheel onto the backing plate and then slide the flapper into the slot. Can be fixed with screws (holes made ready) or double sided tape.