If you’re not familiar with what makes a pattern tessellate as opposed to repeat, think in terms of Pac-Man; when you go far enough to the right side, you come out the left side.
step 1
Start out with a new document. Any dimensions will work. For this example I created a ⅛″ grid on a 2″ square document.
step 2
Draw some objects. The more they break the boundaries of the canvas the better.
step 3
Draw a rectangle the same size as you canvas. You might want to make it a different color if your design is complex.
step 4
- make sure you have snap to grid on
- select all
- group
- copy & paste dragging rectangle created in previous step to all edges and corners of canvas (for a total of 8 pastes)
You should now have 9 copies of your original drawing in a 3 × 3 grid. If your drawing is opaque, some of the repetition will be obscured. Reduce the opacity of your original drawing to, say, 50% and start over.
step 5
- draw another rectangle outlining your canvas
- cut it
- select all
- group
- paste in place
- select the group you just created, then the rectangle you just pasted
- set clip (object > clip > set)
Now your tessellation is ready to be repeated.
Note: If your original drawing is more than 2× the width and / or height of your canvas, you will need to paste your drawing additional times in step 4. I think these are the interesting tessellations because you have to see the pattern repeated many times in order to see the original design.