If you are learning any musical instrument and you are begening to learn intervals this 3-octaves piano will be very usefull, so, let's get started!
Step 1: What will you need
Step 2: Measure the foamy
You can make a piano of one octave, two, three or watever you want; it depends in the size of the whit foamy, for a three octave piano use a 28cm by 28 cm piece of foamy.
Step 3: Cut the white part
Cut through the lines that you have drawn
Step 4: Math
if your piano is of 3 octaves:
28 divided 4 equals 7
the black notes should have 7mm of wide.
Cut the black notes
Step 6: Stick
stick the black notes over the white part, in this patron:
Step 7: Done!
Done! now you can practice the intervals in your little foamy piano.