Here's something to cover your empty wall with: a poster designed by Antumbra.
This is a cheat sheet to help you memorising some music theory.
• 54 different chords in C
• 16 scales
• Circle of fifths
• An octave with key names, half and whole steps illustrated
• 88 piano keys each with note number and frequency in Hz
You can download this poster for free to print it yourself (PIY), or you can buy it printed from Society6.
If you PIY it, please consider a donation even as little as 1€ to keep me going for more stuff.