
previous

page 22
next
The Four Turtles Puzzle
Time to explain what this is!
Imagine four turtles on the corners of a square. Each turtle now heads towards its nearest neighbour (clockwise) - what paths will they end up following until they meet in the centre?
You'll need one more function before you can work on this puzzle:
// set t1's heading towards t2
function towards(t1,t2) {
var x1=t1.x; var y1=t1.y;
var x2=t2.x; var y2=t2.y;
var dx=x2-x1; var dy=y1-y2;
if (dy==0) {
var h=90*Math.sign(dx);
} else {
var rad=Math.atan(dx/dy);
var h=rad*180/Math.PI;
if (dy<0) h=180+h;
if (dx<0 && dy>0) h=360+h;
}
t1.h=h;
}
function towards(t1,t2) {
var x1=t1.x; var y1=t1.y;
var x2=t2.x; var y2=t2.y;
var dx=x2-x1; var dy=y1-y2;
if (dy==0) {
var h=90*Math.sign(dx);
} else {
var rad=Math.atan(dx/dy);
var h=rad*180/Math.PI;
if (dy<0) h=180+h;
if (dx<0 && dy>0) h=360+h;
}
t1.h=h;
}
My solution is on the next page but you have enough tools to solve it yourself!
previous
next