Definitions of Square Dance Calls and Concepts
Big Block CONCEPT [C3A]

From Interlocked Blocks, Butterfly, "O" or other applicable formations.

Execute the given call working within Distorted Parallel Lines. At the completion of the call, each dancer must occupy one of the footprints of the original formation.

Big Block CONCEPT:

 From here... or here... or here... Think of working here.

 beforeBig Block In Roll Circulate after

Notes:
• Shape-changing calls are allowed only if it is possible for each dancer to unambiguously end on one of the footprints of the original formation.
• For complicated calls and shape changers from Interlocked Blocks: memorize the orientation of the diagonal, compress the formation into Parallel Lines, do the given call, then re-establish the Interlocked Block footprints with the original diagonal. See example below:

 beforeBig Block Counter Rotate 1/4 aftercompressing to a normal setup afterCounter Rotate 1/4 afterre-establishing footprints (done)
In the above example, imagine that you are the dancer indicated by. When looking at the left-most formation, you might think that on a Big Block Counter Rotate 1/4 you would end up in the position initially occupied by(which, in fact, you would if the call was Big Block Centers Counter Rotate 1/4, but instead, because of the shape-changing aspect of the call, you should end up on the position initially occupied by dancer.)
• It is not always desirable to compress the formation, do the call, and then re-establish footprints. Starting from the same formation as in the above example, if the call was Big Block Split Counter Rotate 1/4, it would be awkward to compress, do the call, then re-establish. Please only use the compression method when the call is complicated or is a shape-changer.

Variation: Big Block anything To A (Normal) Column | Line | Wave: Start the call working Big Block but end in a normal setup (e.g., Parallel Waves).

Stagger Concept [C2]: From an appropriate 16-Matrix formation, typically Interlocked Blocks. Execute the given call working within Distorted Columns. At the completion of the given call, each dancer must end on one of the footprints of the original formation. Shape-changing calls are allowed with the restriction that it must be possible for each dancer to unambiguously adjust to end on one of the footprints of the original formation. As with Interlocked Blocks, the diagonal acts as the controlling feature for re-establishing the footprints of the resulting formation.