Euclid's Proposition 7 and us

http://gogeometry.com/geometry/euclid_elements_book_i_7_straight_line_congruence.htm

Each living "sibling" from the same parents is inherently different, whatever the "sibling" or "parents" may be in form or substance.

Euclid's Elements Book I, Proposition 7: Given two straight lines constructed on a straight...

gogeometry.com

Euclid's Elements Book I, Proposition 7: Given two straight lines constructed on a straight line (from its extremities). College Geometry,