Got to love this quote from the "Einstein Problem" page on Wikipedia: https://en.wikipedia.org/wiki/Einstein_problem https://en.wikipedia.org/wiki/Einstein_pro

Got to love this quote from the "Einstein Problem" page on Wikipedia: https://en.wikipedia.org/wiki/Einstein_problem https://en.wikipedia.org/wiki/Einstein_problem "Depending on the particular definitions of nonperiodicity and the specifications of what sets may qualify as tiles and what types of matching rules are permitted, the problem is either open or solved."