> ppww("rib_warp", "2/1", warp = 7, weft = 9)
/ - - - - - - - - - \ 
| X   X   X   X   X | 
|   X   X   X   X   | 
| X   X   X   X   X | 
| X   X   X   X   X | 
|   X   X   X   X   | 
| X   X   X   X   X | 
| X   X   X   X   X | 
\ - - - - - - - - - / 

