Once you know a basic block, there are always variations you can make. Changing colour layout is the easiest way to get something new, as you saw last week in the donut block.
Another fun change is to imagine the block cut in half, and do the two sides with different dark and light orientations. I don’t know if there is an official name for this, but I call it a negative block.
To do a negative churn dash, you need slightly different pieces than the regular churn dash. The outer columns are made the same, just the centre one is different. For a 12″ block, you need:
four 4-1/2″ HSTs
three each light and dark 2-1/2″x4-1/2″
four each light and dark 2-1/2″ square
Join the rectangles and squares to make 4-1/2″ squares.
Here is the block layout. You can see one side has a dark background, and the other has a light background. For this layout to be effective, you need to have a strong contrast. If you use fabrics too close in value, you don’t see the design. Lights and darks are far better than mediums.
And once it’s sewn together, it is even more clear.
Any block can be made into a negative block, but it’s easiest to start with some simple traditional blocks. If you don’t have a pattern, try drawing it on graph paper first to help keep track of what goes where. Remember that for squares and rectangles, just figure out the finished dimensions and then add 1/2″ to both the length and width, and that give you your seam allowances.