What if a nuclide were to undergo two successive decays such that it became the original nuclide? Which decays could account for this? Provide an example.

Beta decays and consequent alpha decay accounts for a nuclide undergoing two successive decay to produce the original nuclide. An example of such a nuclide is an isotope of thorium which undergoes two successive beta decays followed by one alpha decay to produce the original thorium.