Ink and pencil
![](../../../images/art/pencil/unknown/mesa-vista-high-school-01.jpg)
Op Art + Zentangle. Penrose Triangle
Excellent combo - original idea by student artist. Mesa Vista High School in Ojo Caliente, New Mexico.
The name of the author is unknown.
The image was found at https://ru.pinterest.com/pin/536772849314808670/