function minLinearDist(A, B) {
  return Math.min(
    // vertical distances (4) between all edges
    (A.y) - (B.y), 
    (A.y + A.height) - (B.y + B.height),
    (A.y) - (B.y + B.height),
    (A.y + A.height) - (B.y),
    // horizontal distances (4) between all edges
    (A.x) - (B.x), 
    (A.x + A.width) - (B.x + B.width),
    (A.x) - (B.x + B.width),
    (A.x + A.width) - (B.x),
  );
}