l'effet papillon or

The butterfly effect is one of the terms related to the Chaos theory. The phrase was coined by Edward Lorenz a meteorologist who discovered chaotic behavior in differential equations.

Lorenz gave a lecture in 1972 titled: “Does the flap of a butterfly’s wings in Brazil set off a tornado in Texas?” This discovery followed an incident when a weather researcher created computer modules to calculate weather. At one time, he stopped the calculation and continued it by copying the numbers manually on a piece of paper. He later inserted the numbers back into the program – receiving dramatically different results from the ones given by simply using the program from beginning to end. The reason for the change is that the numbers in the computer were much more accurate than the ones that were manually copied by the researcher and re-entered ( When he manually re-entered the numeric data, He only entered the figures with 3 digits right of the decimal). This lack of extreme accuracy barely caused any change in the data but due to the complexity of the module, it completely reversed the outcome. The phrase is derived from the understanding that each and every tiny change (a flap of a butterfly's wings...) affects the entire system.

The engraving on the pendant is taken from CHAZAL's ancient saying: "The one who plants a wind will reap a storm" (Hazor'ea rouach yiktzor sufa). Every action that we do, especially an irresponsible one, can have overcoming implications, both positive and negative. 
The tab of the pendant is shaped like the Hebrew letter "PEH" with its inner void creating the letter "BEIT". This symbolizes g-d's words (PEH is mouth in Hebrew) creating all things in the process of creation (BRIAA in Hebrew).