When you plot several data series RainPro will work through a standard sequence of colours, shading patterns, markers and so on. These series have been intentionally chosen to be of varying lengths to reduce the chance of any two data-series being plotted in the same combination. By default, all lines are drawn using the same line thickness (fine).

To over-ride the nib weight cycle:

ch.Set 'nibs' 'fine,medium'
ch.Set 'nibs' 2.1 3 2.2

You can give names or numeric values here. The numbers give the line-thickness in points.

The cycle will persist from the point where you set it, until you set this property again – this allows you to set it once only for a series of several plotting calls.

See also ...
Colours – set colour cycle
Lines – line-style cycle
Markers – marker cycle
Nib Weights
Patterns – pattern cycle