Pectin is a fruit-derived hydrocolloid most often found in jams, jellies, and marmalades. Citrus fruits (particularly dried orange peels) and apple pomace are common sources. Common jam-related treats include thumbprint cookies, jammy dodgers, fruit tarts, fruit tarts, and jelly rolls.
Here's my attempt at doing a more painterly style. Something that'll require some more experimentation on my part :).
And here are the other two for the series:
Next up... Gum Arabic! The first one unrelated to food :P.