This is John F. Ehlers "Sine Wave Indicator" on the book "Cybernetic Analysis for Stocks and Futures".
When red crosses under blue there is a resistance and the price should fall and when red crosses over blue there is a support and the price should rise, but, the market is always right,
if instead of turning down on the resistance it surpasses it there is a trend up, if instead of turning up on the the support it falls through it there is a trend down.