Reading figures - thirds, and the arpeggio
If the distance between two notes is two staff positions, such as from a line to a line, or a space to a space, the distance between them is called a 'diatonic third'.
On an instrument, this equates to moving two steps up or down in a given scale, and for C major, means lifting or placing two fingers in sequence.
The most common pattern where you'll see thirds are arpeggios, which in their simplest form consist of two stacked thirds, like this (ascending and descending):
The ascending arpeggio, and descending arpeggio are two figures that are well worth learning because they slow up everywhere in music.
Here are the ascending arpeggios, from every note on the instrument:
And descending:
All 3 note figures in C major using seconds and thirds
Here are all of the figures possible using seconds and thirds, up to a length of 3 notes, within the range of a 10 hole C ocarina.