Please, explain me this:

[Paufer]

I was reading PAK-9's progamming guide, in the superscope section, when realized that this will draw a square:

INIT:
n=6;
x1=0.5; y1=0.5;
x2=0.5; y2=-0.5;
x3=-0.5; y3=-0.5;
x4=-0.5; y4= 0.5;
x5=-0.5; y5=0.5;
x6=0.5; y6=0.5;

FRAME:
curpoint=0;

POINT:
curpoint=curpoint+1;
x=(if(equal(curpoint,1),x1,
if(equal(curpoint,2),x2,
if(equal(curpoint,3),x3,
if(equal(curpoint,4),x4,
if(equal(curpoint,5),x5,x6))))));

y=(if(equal(curpoint,1),y1,
if(equal(curpoint,2),y2,
if(equal(curpoint,3),y3,
if(equal(curpoint,4),y4,
if(equal(curpoint,5),y5,y6))))));


BUT, why this draws a square:

Init

n=5;

Frame

Rot=0;
Point=0;

Beat

Point

x1=-equal(point,0)+equal(point,1)+equal(point,2)-equal(point,3);
y1=equal(point,0)+equal(point,1)-equal(point,2)-equal(point,3);

x1=x1*0.5;
y1=y1*0.5;

x=x1*cos(rot)-y1*sin(rot);
y=x1*sin(rot)+y1*cos(rot);

point=if(equal(point,3),0,point+1);


WHY??????????

ok, I know it's a rotating square, but still is a square...


Thanks in advance.