Tessellation pictures are unique images. According to Tessellations.org, the image consists of "repeating shapes or patterns that cover a surface without gaps or overlaps." Therefore, a tessellation is a single design that covers an entire surface, whether that surface be flat or three dimensional. Making a tessellation requires that the image fit into a geometric shape, such as a triangle, so keep that in mind when drawing. Although a tessellation picture can be made with a pencil and paper, it is much easier to use a drawing program. Either way, the steps are basically the same.
Using the pen tool in your drawing program, draw a wavy line about two inches long.
Create a new layer by selecting "Layer" and "New." Copy the line you drew in Step 1 then paste it into the second layer. While on the second layer, select "Image," "Rotate" and "Custom" to set the rotation to 60 degrees. Click on the "Move" tool in the sidebar toolbox and move the second line so one end of it meets the end of the first line. Your lines should form a rough "V."
Add another layer to your layers palette and draw a straight line connecting the ends of the two wavy lines. This forms the third line of the triangle, which is called the construction line. Mark the center of the third line with a very short perpendicular line.
Create a new layer and draw a short wavy line from one end of the construction line to the mark you made in the center of the construction line.
Copy the short wavy line from the fourth layer. Add another layer and paste the line on it. Rotate the line 180 degrees and move it to touch the end of the line on the fourth layer. The two short, wavy lines should now have formed one longer wavy line, which rests on top of the straight construction line. Overall, you should have a triangle with three wavy lines. Under the third wavy line, you still have your construction line.
Remove the layer that contains the construction line by clicking on the layer and dragging it to the trashcan icon.
Copy and paste your image as many times as necessary to fill your surface. Change the colors of alternate copies to make them stand out from one another. In some cases, if the two copies don't fit together properly, you may have to rotate the copy 60 degrees.