Types

The spans generated by a Factory are filled with Figure Segments. These probabilities control which types of segments are supposed to occur.

Segments: Segments that are controlled by the settings you make on the Segments tab. These are mostly melodic runs.
Arpeggio: Segments running up and down the line grid in a triangle-like shape. Depending on the symbol type, you get an arpeggio for chord symbols or a melodic run for vertical or horizontal symbols.
Octaves: Segments alternating between 0 and 7, which however is not necessarily always an octave, depending on the current scale.
Ostinato: Segments repeating the same symbol multiple times.
Ornaments: Grace notes or trills.
Glissandos: Segments gliding up or down the grid very quickly.

Variations

Variations: Controls how likely individual segments are transformed, e.g. flipped upside down or reversed.
Stacking: Controls how likely two copies of a segment are stacked above each other.
Interval: The scale steps between stacked segments.

Important: How many symbols are actually filled into a span depends on the Step parameter generated internally by the Factory and the length of the span. There may be spans that come up empty, because none of the steps happen to fall into that span. Likewise, there may be spans too short to contain enough of a segment type to make it recognizable as such. That is, you might get only one or two symbols where an arpeggio or melodic run is supposed to appear.