Pair of Redware Pottery Cups

These stand 2 1/8" tall and measure 2 1/2" across the top. Brown outside and chartreuse inside. Both have the same mark on the base. Hoping someone knows who made these.

 

Studio pottery? MA, NA, AN -- several choices there.

 

Thanks Kent, I thought they were interesting.

 

I like the simplicity and the colors.

 

Wondering if this is William Alexander's mark
https://www.themarksproject.org/marks/alexander

 

Possible, but hard to make a W out of that mark