Exemplar code for the Chapter 3 project Scales and Intervals in the book Coding and the Arts (creativecodingbook.com). Paste into Sonic Pi to run.

Chapter3_Interval_Exemplar.rb

use_bpm 120

current_note = 60
play(current_note)
sleep(1)

# C Major scale using single variable

current_note = current_note + 2
play(current_note)
sleep(1)

current_note = current_note + 2
play(current_note)
sleep(1)

current_note = current_note + 1
play(current_note)
sleep(1)

current_note = current_note + 2
play(current_note)
sleep(1)

current_note = current_note + 2
play(current_note)
sleep(1)

current_note = current_note + 2
play(current_note)
sleep(1)

current_note = current_note + 1
play(current_note)
sleep(1)

# Minor scale using a list of intervals and a loop

intervals = [0, 2, 1, 2, 2, 1, 2, 2]

8.times do |index|
  current_note = current_note + intervals[index]
  play(current_note)
  sleep(1)
end