How to get an interference pattern?

We will hang it above the water surface on the old wooden rod, with two nails driven into it. With vertical vibrations of the rod with a period T, the nails, simultaneously touching the water at points O1 and O2, cause periodic displacements of water particles in them. As a result, waves from two sources spread over the water surface. When these waves are superimposed on the water surface, a stable oscillation pattern is formed, which is called interference.

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