The pyramid puzzle you provided follows a logical pattern where each block is the sum of the two blocks directly beneath it. Here's how we can determine the missing number:

1. At the bottom row, we have the numbers: $1, 3, 5, 2$.
2. Moving up to the next row:
   • $1 + 3 = 4$,
   • $3 + 5 = 8$,
   • $5 + 2 = 7$.

So the second row from the bottom is $4, 8, 7$.

3. Moving to the next row:
   • $4 + 8 = 12$,
   • $8 + 7 = 15$.

This gives the next row as $12, 15$.

4. Finally, the top block will be:
   • $12 + 15 = 27$.

Thus, the missing number is 27.

Would you like more details or have any further questions?

Here are five related questions for deeper understanding:

1. What would happen if we changed the numbers in the base row?
2. Could this puzzle be solved using multiplication or a different rule?
3. How does this pyramid pattern apply to other types of number sequences?
4. Can you find any other types of puzzles that use a similar summation concept?
5. How would this pattern change if we introduced negative numbers?

Tip: Always look for patterns in puzzles like this by examining how each number relates to those around it.