self esteem
A 19th century perpetual motion machine powered by steam, theorized by Alberto Einstein but no actual production models were ever built.
Example:
Alberto told the eager investors gathered in Plaza de Suenos that for as few as 500 Pesos they could own a piece of his revolucionary self esteem engine.
Alberto told the eager investors gathered in Plaza de Suenos that for as few as 500 Pesos they could own a piece of his revolucionary self esteem engine.