An ominous-sounding ‘Hindenburg Omen’ and a ‘Ohama Titanic Syndrome’ are forming in a key stock-market index

A pair of ominous patterns are forming in the Nasdaq Composite, which could signal that a stock-market climb, fueled by a hoped-for tariff detente between the U.S. and China, may be starting to unwind—or at least stall out.