Step 1:
I used green papers in various sizes and color variations.
Prefold in half over these four lines.

Step 8:
Press inwards, not completely.

Step 6:
Sink-fold the center over the prefolded lines.

Step 11:
Make cactuses in various sizes and color variations.

Step 10:
Make these folds on all eight corners.

Step 9:
Fold all eight edges downwards.

Step 5:
Prefold over this line and open the model.

Step 7:
Here a part of step 6 is done.

Step 3:
Prefold over these two lines.

Step 2:
Fold over the two lines at the bottom right, then over the two diagonal lines. And then over the two lines at the top left.
All folding lines are prefolded.

Step 4:
Fold these two edges inwards over the prefolded lines (Make the same folds, valley-folds, on the layer below).
Repeat steps 3 and 4 on the backside.

Step 12:
I glued the cactuses in a basket filled with paper.
I used brown paper balls as extra decoration.

Done!
This is a DIY video tutorial for making the Barrel Cactus:

Picture:  Origami Cactuses in a white basket