Show/ hide buttons added to each output block.
Show/ hide buttons added to each output block.

chenleo/ipynotebook,nntisapeh/intro_programming,ehmatthes/intro_programming,nntisapeh/intro_programming,BadWizard/intro_programming,BadWizard/intro_programming,nntisapeh/intro_programming,chenleo/ipynotebook,chenleo/ipynotebook,chenleo/ipynotebook,BadWizard/intro_programming,nntisapeh/intro_programming,ehmatthes/intro_programming,ehmatthes/intro_programming,ehmatthes/intro_programming,BadWizard/intro_programming