a(z) = - _
z
 



b(z) = 2 - _
z
 



g(z) = _
z
 



gba(z)
=
gb(- _
z
 
 )
=
g(2- _
(- _
z
 
 )
 
 )
=
g(2+ z)
=
2 + _
z
 
Hence this combination of 3 reflections increases the x coordinates of each point in the shape by 2 units thus translating it 2 units forward while mapping each y coordinate to -y thus reflecting the shape in the real axis, so producing a glide reflection.