Invite a number of people for a roast meal. Put meat and potatoes in oven to roast. Put large white pumpkin on chopping block. Cut a wedge out of the pumpkin. Commence to cut the skin off. Get side-tracked by the interesting combination of colours on the pieces of skin. Arrange pieces in a pleasant arrangement. Photograph. Transfer image to computer. Open image in Photoshop and apply 'posterise' filter.
Luckily pumpkins don't take long to roast.
Here's the original: