Cyclohexane chair flip (ring inversion) reaction. Structures of the significant conformations (A, B, C &amp; D) of the reaction are shown. Inversion happens quickly &amp; constantly in room temperature.
Conformations:
1: chair (lowest in energy)
2: half-chair (highest in energy)
3: twist-boat
4: boat
When ring flip happens completely from chair-to-chair, hydrogens that were previously axial (blue H) turn equatorial &amp; equatorial ones (red H) turn axial.
Pink and orange arrows show how one can imagine how carbons are being "pushed" as one conformation turns into another.
Source for the conformation names &amp; claim of lowest/highest energy:

J Clayden, N Greeves, SG Warren (2001). Organic chemistry. (2nd ed.). p. 373. ISBN 9780191666216.
Own work
Keministi