-Bit-mask is usage of one byte (8 bits) as 8 separate bits with it's own meaning.
-So, 1 = 2^1, thus it's bit 1. So, for 1-3 we have:
+Bit-mask is usage of one byte (8 bits) as 8 separate bits with it's own
+meaning (this is simplification, but bear with me for now).
+
+So, 1 = 2^0, thus it's bit 1. With analogy, 2=2^1 and 3=2^0+2^1.
+So, for 1-3 we use two bits and have: