Question:
Given a Tuple for eg. (a, b, c).
Output : (*, *, *), (*, *, c), (*, b, *), (*, b, c), (a, *, *), (a, *, c), (a, b, *), (a, b, c)

This question can also be asked as print all subsets of a given set.

Answer:
This looks that a character in the tuple can either be '*'' or itself. So we simply need to choose one character at a time, print combination on remaining substring and add them with '*' and earlier chosen character.

If we notice, it will be like below in reality:

This can be simply achieved by recursion. We just need to identify correct boundary conditions. Below is the code for the same. In this code, I have taken string in place of tuple but the logic stays same.

```def pattern(prefix, input, len)
# boundary condition
if (prefix.length == len)
puts prefix
return
end

pattern(prefix+input[0], input[1..-1], len)
pattern(prefix+'*', input[1..-1], len)
end

# for test, I took only abc, you can take the input as argument
input = "abc"
pattern("", input, input.length)
```

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