markbarendt is right. Look how "cheap" these transparent step wedges are. They last a lifetime. I've found no other cheap photo accessory as useful as a step wedge - considering how much cost of material and trouble it is to makeshift without one...
Originally Posted by markbarendt
But if the idea is a journey to understanding, then any path that gets you there is fine. Just like climbing straight up a rock gets you to the top, same as taking a walk up the backside.
Considering OP wants to make a test pattern for traditional testing, I think it's OK to talk.