Primary Uptrend Support Lines are straight lines in charting which connect at least two price bar lows, and where there are no breaks when extended in either direction (which differentiates them from Secondary Lines). Additional data points will strengthen the relevance of a support or resistance line, somewhat like exponents in math.
Naturally Rising Support
Previous Primary Lines can assist in determining the current health of a company (or whatever else is being charted). Their present value naturally rises through time at a constant rate, until a downtrend takes them out or the charted entity ceases to exist.
In a Curved Universe
the Straight Line is King!