Hmm, these tadpoles are an excellent subject by themselves and can trigger several unrelated thoughts even related to formation of life too.
Of all the four versions my favorite is the second one titled "Birth of an idea - 1947". Grains, tone, quality of water, reeds all add up beautifully there. Further that images seem to relate to something in mind and make me ponder over what that is. In this image I think due to extreme contrast dimension is lost. But I kind of like the graphic appeal. It would be interesting to know what triggered you to title the other image as "Birth of an idea - 1947". Thanks for sharing..