__H1
__H1(a) = __H2(a) = __H3(a) = 0;
__H1(a) = __H2(a) = __H3(a) = 0;
__H1(a) = x1;
__H1(a) = x1;
x1 = __H1(x);
y1 = __H1(y);
__H1(a) = __H2(a) = __H3(a) = 0;
__H1(a) = __H2(a) = __H3(a) = 0;
__H1(a) = x1;
__H1(a) = x1;
x1 = __H1(x);
y1 = __H1(y);