Print out a clear drawing of the Aztec calendar. This drawing needs to have distinct lines for each of the inner circles so that you can measure them for your carving. Measure the circumference of each circle with a protractor.
Mark each circle on your soft wood board with a dark lead pencil. Draw these lines dark enough to keep them distinct. On the Aztec calendar, the pattern changes within each circle.
Set the print of the Aztec calendar in front of your worktable where you can see it clearly. Draw the designs in their respective circles on your wood board. This tracing will guide your carving.
Carve the circles into the soft wood with your X-Acto knife. Hold the handle of the blade in your palm and brace your pointer finger on the soft side of the blade. Dig a shallow carving your first time through.
Repeat Step 4 for the details in your Aztec calendar. Complete a shallow carving first, then go back over it to make it deeper if you wish. If you mess up on a shallow carve, you can always fix it with a deeper carving a second time through.
Cut your circular calendar out of your wooden board with a router and guide. Measure the circle, set your router to the appropriate measurements and cut.
Clean the edges of your calendar with your X-Acto knife. Scrape away leftover pieces for a smooth finish.