The boxxyerrorbars style is only relevant to 2D data plotting. It is similar to the xyerrorbars style except that it draws rectangular areas rather than simple crosses. It uses either 4 or 6 basic columns of input data. Additional input columns may be used to provide information such as variable line or fill color (see `rgbcolor variable`).
4 columns: x y xdelta ydelta
6 columns: x y xlow xhigh ylow yhigh
The box width and height are determined from the x and y errors in the same way as they are for the xyerrorbars style—either from xlow to xhigh and from ylow to yhigh, or from x-xdelta to x+xdelta and from y-ydelta to y+ydelta, depending on how many data columns are provided.
The interior of the boxes is drawn according to the current fillstyle. See `set style fill` and boxes for details. Alternatively a new fillstyle may be specified in the plot command.