code: function iterPush(ptr,
    axis, 
    redStart, redEnd, 
    blueStart, blueEnd, 
    state, 
    lo, hi) {
  
    var iptr = IFRAME_SIZE * ptr
    BOX_ISTACK[iptr]   = axis
    BOX_ISTACK[iptr+1] = redStart
    BOX_ISTACK[iptr+2] = redEnd
    BOX_ISTACK[iptr+3] = blueStart
    BOX_ISTACK[iptr+4] = blueEnd
    BOX_ISTACK[iptr+5] = state
  
    var dptr = DFRAME_SIZE * ptr
    BOX_DSTACK[dptr]   = lo
    BOX_DSTACK[dptr+1] = hi
  }
docs: Append item to queue