lesson of geometry, simplified

somewhere in the UES - if I remembered where, I'd link you to a map but... [L]
Oh boy, oh boy... only six of you ventured to resolve one of the four problems of yesterday's lesson. Marley, Amy and Babzy: bravo! Daryl, Hyde DP and Marie-Noyale: B for effort.
So today, I revised my educative pretensions. Simplicity is the key word here. Therefore we will concentrate on the basics: stripes, parallel lines. And if you pay attention, you will notice that not all the lines in this picture are parallel.
Tomorrow, we'll introduce a touch of poetry.