Color A   ----------+           +-----------+           +----------
                    |           |           |           |          
Color B             +-----------+           +-----------+          
           Block n        ...      Block 3     Block 2     Block 1
         <---------> <---------> <---------> <---------> <--------->
 
                             Traffic Flow           
         ===========================================================>
Color   ...AAAAAAAAAAA BBBBBBBBBBB AAAAAAAAAAA BBBBBBBBBBB AAAAAAA...
         ===========================================================>