You can use the strips you have to randomly construct strata that are 2-strips wide and 3-strips wide. Press and spray starch, then cut your pieces out of those strata. Save remnants for a mile-a-minute quilt (where you randomly sew fabric scraps together, press and spray starch, then cut the shape you want).
The only reason they tell you to cut WOF is because that way you can cut multiple shapes out of the strata. You can create strata out of shorter pieces; you just won't cut as many shapes out of each strata.