I already posted about this one more than a year ago and instead of updating the post itself I decided to create a new one since it has grow up so much. It's everywhere, in all the Taksim, Cihangir, Maçka, Tophane area. I couldn't put all of them in here but you get the idea.
I spotted this one in the Tophane district down at the corner of Meclis-i Mebusan boulevard and Salı Pazarı Yokusu. It was done pretty recently I guess because I've been there on scout not too long ago and I didn't see it. I really like the design of this one. The way it runs. 20x20 cm. If you look well you can see a very small one on the second photo (on the right) representing a small "guy" standing still with a big heart linked to his brain as well.
I found this one between the Cihangir (Djeehangear) and the Tophane District in the Ilyas Çelebi Street (Google Maps). The person on this purple stencil looks like a friend of mine, a girl who is crazy about purple but she's not a student. The stencil says : Okullar Açılmasa : If only schools wouldn't start. Its size is about 25x25 cm.