Square-law based RBF kernel

Question

What is the Square-law based RBF kernel (SQ-RBF)? The definition in the table at the Wikipedia article Activation Function looks wrong, since it says

y = 
     1 - x^2/2     for |x| <= 1
     2 - (2-x^2)/2 for 1 < |x| <= 2
     0             for |x| > 2

but this makes it discontinuous at x = 1