I've added text on two of the bigger heart pieces on the 1-2 gear, LOVE YOU
The heart plates are named by their gear ratio, so 1-2 is 1 : 2, etc. 1-2 has a period of one revolution, while 2-3 is two and 5-6 takes five revolutions, so don't give up.
Credits: Three Heart Gears by emmett - Thingiverse
Instructions, old video (Let me know if you need additional instructions)