Choreographer’s sketching at Auditório Fernando Lopes-Graça.

What the Etymology Dictionary also  says about the word

‘sketch’

(…) from Italian schizzo “sketch, drawing,” lit. “a splash, squirt,” from schizzare “to splash or squirt,” of uncertain origin, perhaps from Latin schedium “an extemporaneous poem” (…)

Etymology Dictionary © 2010 Douglas Harper