+=item B<PART> : I<vname> B<#> I<rrggbbaa> [ B<:> I<legend> ]
+
+B<RRDtool> has now support for B<pie charts>. If you include the
+B<PART> command, the canvas is extended to make room for a chart
+The size of the canvas is determined by the lesser of
+L<width and height|rrdgraph/item_Size>.
+
+Pie parts will be concatenated, the first one will start at the
+top and parts will be created clockwise. The size of the part
+is defined by the value part of the L<VDEF|rrdgraph_data/VDEF>
+function. It should return a number between 0 and 100, being a
+percentage. Providing wrong input will produce undefined results.
+
+=item B<TICK> : I<vname> B<#> I<rrggbbaa> [ : I<fraction> [ : I<legend> ] ]
+
+Plot a tick mark (a vertical line) for each value of I<vname> that is
+non-zero and not *UNKNOWN*. The I<fraction> argument specifies the
+length of the tick mark as a fraction of the y-axis; the default value
+is 0.1 (10% of the axis). Note that the color specification is not
+optional.