
Polish graphic designer
Jacek Walesiak invites us to celebrate some of the modern, more off-kilter holidays and observances through a special, commemorative run of postage stamps that also fête the country’s rich op art heritage. The collection includes sheets that mark International Day of Vegetarianism (
1 October), International Sock Day (4 December), Towel Day (25 May), Trolley Drivers’ Day (see also) and International Day of Caps Lock (observed semi-annually on 28 June and 22 October).