Editing Dragon curve (section)

=== Folding the dragon ===
The Heighway dragon curve can be constructed by [[regular paperfolding sequence|folding a strip of paper]], which is how it was originally discovered.<ref name=tabachnikov/> Take a strip of paper and fold it in half to the right. Fold it in half again to the right. If the strip was opened out now, unbending each fold to become a 90-degree turn, the turn sequence would be RRL, i.e. the second iteration of the Heighway dragon. Fold the strip in half again to the right, and the turn sequence of the unfolded strip is now RRLRRLL – the third iteration of the Heighway dragon. Continuing folding the strip in half to the right to create further iterations of the Heighway dragon (in practice, the strip becomes too thick to fold sharply after four or five iterations).

[[File:Dragon curve paper strip.png|center|800px]]

The folding patterns of this sequence of paper strips, as sequences of right (R) and left (L) folds, are:
* 1st iteration:  R
* 2nd iteration: '''R''' R '''L'''
* 3rd iteration:  '''R''' R '''L''' R '''R''' L '''L'''
* 4th iteration:  '''R''' R '''L''' R '''R''' L '''L''' R '''R''' R '''L''' L '''R''' L '''L'''.
Each iteration can be found by copying the previous iteration, then an R, then a second copy of the previous iteration in reverse order with the L and R letters swapped.<ref name=tabachnikov/>