I was astonished to read a letter criticising my cartoon for containing a "negative racial stereotype" and "disparaging indigenous art as crude and childlike". The joke was that an indigenous Australian artist had included a degree certificate in his painting as an ironic reference to having dropped out of a fine arts course. He is pointing this out to a white Australian friend.
His painting includes animals often seen in indigenous Australian art. That does not mean there are not lots of indigenous Australian conceptual artists, but this would be impossible to get across in a small cartoon.
A life of unremitting textual analysis in an English department has led the letter writer to misread the cartoon.