A mathematical colouring book on Kickstarter has raised more than $400000

April 20, 2016     /

from Icetulip http://on.mash.to/20Wft29 via IFTTThttp://on.mash.to/20Wft29 http://ift.tt/1iul9A1 A mathematical colouring book on Kickstarter has raised more than $400,000