styroglyphics 

The act or result of carving doodles into a styrofoam container with your fingernail.

I found some styroglyphics of indeterminate anthropological value while cleaning the fastfood containers out of my car.

styroglyphics by MTQ August 5, 2007

spyroglyphics 

1. The art of using childish handwriting to illude a fellow friend in a letter
2. To create a hidden message inside a well presented text

1. I couldnt read what he wrote, fucker used spyroglyphics

spyroglyphics by Avalar February 25, 2008

stenoglyphics 

a term used for bad, almost unreadable handwriting.

(steno- referring to stenography or shorthand, a way of writing and
-glyphics referring to hieroglyphics)

"Man, this handwriting is hard to read."
"Ask Jane, she can decipher stenoglyphics."

stenoglyphics by @kenopsianxiety November 8, 2018