# Corner in 3D (tripod)

For reference see incontrastsRef.html.

    function q = corner3D(X1,X2,X3, varargin)
    % 3D angle-shaped object (tripod)

    seti = varargin{end};
    R = seti.rCD/2;

    p1 = -4/8;
    l = 7/8;
    w = 1/8;

    p2 = p1+l; % bottom and right
    p3 = p1+w;

    % first horizontal arc of angle
    q1 = 1.0*((p1*R <= X1) & (X1 < p2*R) & (p1*R <= X2) & (X2 < p3*R) & (p1*R <= X3) & (X3 < p3*R));
    % second horizontal arc of angle
    q2 = 0.8*((p1*R <= X1) & (X1 < p3*R) & ((p1+w)*R <= X2) & (X2 < p2*R) & (p1*R <= X3) & (X3 < p3*R));
    % vertical arc of angle
    q3 = 0.6*((p1*R <= X1) & (X1 < p3*R) & (p1*R <= X2) & (X2 < p3*R) & ((p1+w)*R <= X3) & (X3 < p2*R));
    q = q1 + q2 + q3; % interesting is the middle of all arcs...

    q = double(q);
    end