POSITIVE_RUNT and NEGATIVE_RUNT

What do the POSITIVE_RUNT and NEGATIVE_RUNT directions refer to?

Advanced Runt Trigger: Detects a pulse that crosses one threshold and then falls below, or rises above, the same threshold, without crossing the second threshold. This is typically used for finding pulses that fail to reach a valid logic level.

A positive runt is a pulse going in the positive direction that rises above the lower threshold but does not reach the upper threshold.

A negative runt is a pulse going in the negative direction that crosses the upper threshold but does not reach the lower threshold.

Thanks! I noticed an example of this is shown in advanced trigger menu of Picoscope.