You can see the difference also in hand-written ones. The keys are 1)the slope of the upper horizontal line in the left radical(hen), 2)whether the lower horizontal line is written across the vertical line or not, and 3)whether the vertical line is straight or curved.
Another tehen-kemonohen pairs
窶ーナクテ?ツセ
窶敖渉債
ツ抂窶ケツカ
ツ挾テ?テ
Can you decipher the difference between the following pairs?;-)
窶扞テ・テ
窶忱ナスm