Turning blocks vs points vs pieces?

I am starting to get into basic 4-way. So far I've just worked on turning basic points. I hear some of the more experienced people talking about turning points, blocks and pieces. What is the difference between the three?

A point is a completed formation with all grips correct.

Pieces is a transition between two points (formations) where a part (or parts) of the original formation stay linked while flying to the next point.

In a random during the transition between two points all grips are released.

In a block during the transition between the two points a piece or pieces are held and flown back together. Or one piece is held while the other people fly to their next slots.

countzero

In a block during the transition between the two points a piece or pieces are held and flown back together. Or one piece is held while the other people fly to their next slots.

Everything else was spot on - This once was a bit off. Simply put, a block is when there is a mandatory transition between two or more points.

Look at blocks 7, 9, 14, and 15 in the 4 way dive pool...
http://www.rhythmskydiving.com/files/7414/8824/6607/4way_continuity_one_page-blocks_only.pdf

They all have all 4 people moving. So simply put, a block is when there is a mandatory transition between points. In the old days, 8 way had three point blocks.

Watch this video. Clearly shows all the randoms (letters) and blocks (numbers) in the FS divepool. Should clear it all up for you.

https://www.youtube.com/watch?v=Y2B4S3lGf54

I didn't quite get the terminology either, in the beginning:
There are 2 types of formations that can be drawn during competition.
RANDOMS are single formations, such as a "round" or a "bow" and they are abbreviated with a letter (such as M or H)
If you have only RANDOMS in a dive, it does not matter how you get from one formation to the next. It only matters that you break all grips between the formations and have all grips taken simultaneously on the next formation. Each formation counts as one POINT.

On a BLOCK, you have two formations that have to be executed with a specific transition in between (such as: everyone does a 360 turn between the 2 formations) They have to be executed as shown (although they can sometimes be executed as a mirror image and sometimes the turns in the transition have to be in a specific direction and sometimes you can choose)
BLOCKS are denoted with a number instead of a letter and are generally considered more challenging than RANDOMS, which is why they are not included in beginner draws.
They count as 2 POINTS if executed correctly (as there are 2 formations)

Some BLOCKS contain PIECES that turn together. For example: 2 people might stay together in the transition and not release grips, but instead turn as a whole PIECE. In the beginning this makes it a bit more challenging again, but they are really fun, when they work out.

http://jumpoutofaplane.com/images/DivePool_Blocks_and_Randoms.pdf