Te Definition

# Standard Triangle two of whose vertices are A(0,0) , B(1,0) and
# the other vertex, C, is such that angles CAB and CBA are
# 2*arctan(m) and 2*arctan(n) respectively

Te:=proc(m,n):

[0,0]   ,   [1,0]   ,   Pt (  y- TS(m,m)*x   ,   y+ TS(n,n)*(x-1)   )   :

end: