https://www.bu.chsta.be/en/notebook/2013/02/ruby-koans
Ruby Koans | Language Data Processing Laboratory
Feb 24, 2013 - If you are interested in a programmatic way to learn some aspects of Ruby, your might want to look at Ruby Koans.
ruby koansdata processinglanguagelaboratory
https://www.rubykoans.com/
Learn Ruby with the Edgecase Ruby Koans
Learn Ruby with the Edgecase Ruby Koans
learnrubykoans