array(2) {
  [0]=>
  int(0)
  [1]=>
  string(5) "color"
}
array(3) {
  [0]=>
  int(0)
  [1]=>
  int(3)
  [2]=>
  int(4)
}
array(2) {
  [0]=>
  string(5) "color"
  [1]=>
  string(4) "size"
}
array(3) {
  [0]=>
  string(1) "a"
  [1]=>
  string(1) "b"
  [2]=>
  string(1) "c"
}
array(2) {
  [0]=>
  string(1) "a"
  [1]=>
  string(1) "c"
}