Hey, thanks for the detailed feedback!
If you drag your shape (the most bottom one) into the orb below the letters, you can pick a proverb to send with the shape to another player (well, right now the multiplayer is faked…). So your plants need shapes you get from others and you can send your shapes to help out others.
I guess that’s why an in-game tutorial or at least a how to play menu is needed. Will know for next time :)