One move that is seen frequently in several forms is the X block, so-called because it's shape makes the letter X.
This block is designed to both stop an attack from connecting with the body as well as assist in trapping the weapon used. When done high like seen above you're usually stopping a staff weapon from connecting. Turning the hands will trap the weapon such that you can grab it and gain control of it. This move will frequently precede a breaking motion that signifies the breaking of the staff and then another attack using the two broken will ends will follow.
When done low as seen above it's usually stopping an upward kick. Again, the next move usually involves a turning of the hands which signifies grabbing the foot and either sweeping upward to upend the attacker or pulling the foot in to take them off balance and then attack.
Due to the utility of this move it has a lot of bunkai (applications) and is worth further studying by practitioners who want to gain a better understanding of the real-world application of our forms.