t = 0.01:0.01:10;
x = zeros(length(t));

for n = 1: length(t)
    if(t(n) < 6)
        if(t(n) < 4)
            if(t(n) < 2)
                x(n) = t(n)^2;
            else
                x(n) = 4;
            end
        else
            x(n) = -2 * t(n) + 12;
        end
    else
        x(n) = 1/2 * t(n) - 3;
    end
end

plot(t,x);