eTime[c_, maxIter_Integer: 100] := Length@NestWhileList[#^2 + c &, 0, Abs@# <= 2 &, 1, maxIter] - 1 DistributeDefinitions[eTime]; mesh = ParallelTable[eTime[x + I*y, 1000], {y, 1.2, -1.2, -0.01}, {x, -1.72, 1, 0.01}]; ReliefPlot[mesh, Frame -> False]