The attached photo has recently gone viral. The left and right pictures are identical, but placed next to each other they seem to be taken from different perspectives. I did a quick sketch of the picture and on my first try I drew the street curb angles differently comparing left and right photos. But then measuring where they cross the edge of the photo forced me to get them drawn more accurately. I thought this was an interesting exercise, where measurements were absolutely necessary because my perception alone is quite a bit off. It seems that accurate drawing sometimes requires us to completely ignore our perceptions, I noticed I’ve run into this problem more than once, especially with portraits. Do you agree?