Let the horizontal length be H and the vertical jog be V. Then one full cycle is distance 2*(H+V); suppose that it is to be completed in time P (the period.)
WIthin the first period, the horizontal position goes like
s = 2*(H+V)/P; %speed
x = piecewise( MOD(t,P) <= H/P, H-mod(t,P)*s, ...
MOD(t,P) > H/P & MOD(t,P) <= (H+D)/P, 0, ...
MOD(t,P)>(H+D)/P & MOD(t,P) <= (D+2*H)/P, mod(t-D-H,P) * s, ...
MOD(t,P)>(D+2*H), 0)
and you can define the vertical position by similar means, except that the vertical position progresses by 2*D for every full period.
Above, MOD should not be implemented as mod() unless you have R2020b or later. Instead
MOD = @(val,period) val - floor(val/period)*period
This is because in earlier releases, mod() of a symbolic expression gets a bit odd and difficult to work with.
