

% R is a rotation in R^2 of two radians about the origin
R = @(t) [cos(t) -sin(t); sin(t) cos(t)]

% H is a reflection about line a line making an angle of theta with the x-axis
H = @(theta) [cos(2*theta) sin(2*theta); sin(2*theta)  -cos(2*theta)]

% T is a translation matrix, in homogeneous coordinates
T =@(x,y) [1 0 x;0 1 y; 0 0 1]

% 3-d rotation about x-axis
R3x = @(t) [1  0 0; 0 cos(t) -sin(t); 0 sin(t) cos(t)]
R3y = @(t) [cos(t)  0 sin(t) ; 0  1 0 ; -sin(t) 0 cos(t)]
R3z = @(t) [cos(t) -sin(t) 0; sin(t) cos(t) 0; 0 0 1]
