Cardano Explained Without Jargon & Within 199 words
The metaphor with throwing dices
Finding blocks is like a game of throwing a six sided dice with 5 blank sides and 1 side that will give your pool a block (see image above). All stake pools throw once every 5 days. However, the more ada your pool has staked, the more dices your pool gets: 1 dice per 175k of ada. So if your pool has 1 million of ada staked they will get 6 dices. The odds of finding a block per dice is about 17% (1 in 6). So a pool with 1m of stake can expect to find 1 block every epoch (on average). But this is just statistics, since a pool with 20 dices still can be unlucky and only throw blank sides and get zero blocks. This is how the "luck" factor is manifested in the protocol.
Blocks per epoch = active stake divided by 1,000,000. Examples:
20m active stake: 20m/1m = 20 blocks each epoch
1m active stake: 1m/1m = 1 block each epoch
1k active stake: 1k/1m = 0,001 block each epoch -> 1 block every 14 years
If you want the exact numbers check this great calculator.
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