check_second(card) in functions.js
function check_second(card) {
  var ok;
  if (empty(card)) {
    ok=true;
    if (klass(card)=='temp' && g_seq.length>1) {
      ok=false;
    }
  } else {
    if (klass(card)=='temp') {
      ok=false;
    } else if (klass(card)=='final') {
      if (g_seq.length>1) {
        ok=false;
      } else {
        var i=card.id-200;
        var v0=g_final_col[i];
        var v1=first_card_value();
        ok=false;
        if ((v0+1)==v1) ok=true;
      }
    } else { // must be main
      if (last(card)) { // check for sequence
        // convert strings to numbers
        var n1=parseInt(card.id);
        var n2=first_card_value();
        var arr=[n1,n2];
        ok=check_sequence(arr);
      } else {  // is not last in column
        ok=false;
      }
    }
  }
  return ok;
}

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