A million grains of sand is a heap. If we remove one grain of sand from this heap, we will still have a heap.
We can now keep repeating (2) until we only have a single grain of sand remaining.
Is this a heap? Clearly not. But what went wrong with our thinking?
This is called the Sorites paradox (soros being Greek for "heap") and is a classic paradox that has no real answer.
Both (1) and (2) are true, and we can indeed keep removing one grain of sand until we have a single grain remaining. If we remove one more grain, we're left with nothing, is this still a heap?
When does the heap become a non-heap?
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Puzzle 2
The month of March in the year 1980 contained 5 Saturdays and 5 Mondays.
Each term alternates between a square and a cube, 8 3 = 512.
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Puzzle 4
Hidden in the grid below are eight, 7-letter words. Each word begins with the central R and you can move one letter in any direction to the next letter. All of the letters are used exactly once each. What are the words?
T
A
E
R
O
B
O
E
T
G
S
T
N
W
R
N
E
E
A
I
E
I
N
U
R
E
F
R
N
B
U
O
E
E
E
B
S
E
A
E
V
E
I
D
H
T
S
G
N
Note: this puzzle is not interactive, and the letters cannot be clicked.