quad-comparison

// Quadratic time complexity O(N 2 ) — “Order N squared”
function compareAll(active) {
  // loop thru all bodies backwards //
  for(let i = active.length - 1; i > -1; i--) {
    // pull out bodyA for comparison //
    const bodyA = active[i];
    // loop thru all bodies backwards again //
    for(let j = active.length - 1; j > -1; j--) {
      // pull out bodyB for comparison //
      const bodyB = active[j];

      // compare bodyA to bodyB...
    }
  }
}