For the yellow gem, go to Marerijk. In the Marerijk main area, go left to the troll king, represented by the crown. Grab the banana, and leave the poor man alone. Go to Reizenrijk.

In the Reizenrijk area, go left to the carnival, represented by a red clown ball-nose. Feed the banana to the giant monkey's mouth and move the character in front of the gate aside. You can then enter that gate's passage.

Solve the ice puzzle now in front of you by moving all of the pieces to the correct position. Unless you want to, DO NOT click on the igloo, or the puzzle will reset. As usual, clicking on the E will call Belletje Bel, and you'll leave the area.

Once the puzzle is completed, grab the bucket and move back to the Reizenrijk main area. Here, take the middle path to the cannibal, represented by the pot with a spoon in it. At the cannibal's pots, click on one of the pots to start the puzzle.

To solve this puzzle, open Pardoes' inventory and grab the bucket. Fill the bucket with water from the pond on the left and douse the pans in the following order, refilling the bucket with water after each pot: Red, Yellow, Green, Blue, Purple.

Once the victory music stops playing and the man stops talking, you can grab the yellow gem.