Plotting Discontinuous Graph

From one of the problem in here :

I've got some clue from here. So, here is my solution :

t = -5:0.01:5;     % total range of the graph

q1 = t<-4;            % range 1
q2 = t>=-4 & t<3;     % range 2 
q3 = t>=3;            % range 3

y = zeros(size(t));    % initialization

y(q1) = 0;             % curve 1
y(q2) = t(q2) + 2;     % curve 2
y(q3) = t(q3) - 2;     % curve 3

plot(t,y); axis([-5 5 -4 7])

And here is the graph :

Okay. The x(t) above is quite simple. How if it is --in example-- an polynomial equation? The concept remains the same. But, don't forget to use the dot operator, because we will power each of array member.