Front Porch 'No Californians' stickers being slapped on For Sale signs in Portland Updated: Sep. 04, 2015, 10:00 a.m. | Published: Sep. 04, 2015, 9:00 a.m.

Evtimov et al., arXiv.org In a test of a right-turn sign, a mask that filled in the arrow on the sign resulted in a 100 percent misclassification rate.

This stop sign has been covered by a full-size replica that includes subtle camo marks. This was 100 percent effective at fooling their machine into thinking it was also a 45mph speed limit sign.