This puzzle is derived from CodinGame SamSi's "Heart of the City" puzzle.
Description
You decide to take a walk in an n * n tile city and go to the center tile. All of the buildings are infinitely small, but you have super vision and can see everything close up and far away.
Constraints
n is always odd
You can see any building that is not directly obstructed by another one
Task
Mark each building visible with *. The building is visible iff it is not blocked by another building on the exact same line of vision.
In other words, if @ is the origin, the building is visible iff the x-coordinate and the y-coordinate are co-prime to each other.
Example input and output
Input:
7
Output:
** **
* * * *
*******
*@*
*******
* * * *
** **
* is a visible building,
is an invisible building, and
@ is where you are.
Scoring
Remember, this is code-golf, so the answer with the least bytes wins.
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