A heart beat is one of the most recognizable electrical signal displays, which is how I know this isn’t a healthy one. There should be two spikes, close together, but I do what I can with a 9x9 grid.
Rules:
Normal Sudoku rules apply.
Digits in cells marked with a green square are even.
Digits in cells marked with an orange circle are odd.
Estimated difficulty: 1 out of 5
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