Searched the public library and didn't find an existing indicator so I'm publishing my version.
// Elder SafeZone Stops // Converted from http://chartingwithchris.blogspot.com/2008/10/elder-safezone-stop-system-thinkorswim.html //@version=2 study("Elder SafeZone", overlay=true) coeff = input(2.5, "CoEff", type=float) lookbackLength = input(15, "LookBackLength", type=integer) countShort = high > high[1] ? 1 : 0 diffShort = high > high[1] ? high - high[1] : 0 totalCountShort = sum(countShort, lookbackLength) totalSumShort = sum(diffShort, lookbackLength) penAvgShort = (totalSumShort / totalCountShort) safetyShort = high[1] + (penAvgShort[1] * coeff) finalSafetyShort = min(min(safetyShort, safetyShort[1]), safetyShort[2]) count = low < low[1] ? 1 : 0 diff = low < low[1] ? low[1] - low : 0 totalCount = sum(count, lookbackLength) totalSum = sum(diff, lookbackLength) penAvg = (totalSum / totalCount) safety = low[1] - (penAvg[1] * coeff) finalSafetyLong = max(max(safety, safety[1]), safety[2]) p1 = plot(finalSafetyShort, "Short Stop", color=#ff00ff) p2 = plot(finalSafetyLong, "Long Stop", color=#ff00ff)