Rich, Yes, if periodicity checking is on, there is a technical problem with how the bailout condition as written and how periodicity is checked. Periodicity checking should not change the appearance of an image, it should just speed up the calculation of the image. But with this formula, the periodicity checking could cause the bailout to occur at different pixels. There are other problems, however. See below. Yes, this is documented. Perhaps not enough, and I don't know what the tutorial says about this. Yes, this is also a side-effect of the current parser implementation. No, it is not a bug. It is not possible to force users to always write "technically" correct formulas. The parser puts certain predefined variables into an array of complex pairs of numbers. Some of these variables are pixel, p1-p5, z, LastSqr, pi, e, and rand. The parser always knows where to find these variables. For example, z is v[3]. The location of user defined variables is not set. The parser puts the value of z into the complex variables old and new at the end of the iteration or when the bailout condition is reached. There is no way for the parser to know when z is not being used in the bailout condition. The value of new is then used to calculate the inside and outside colors for options that are not based on the iteration count. This causes the other problems. Since z (new) and the bailout condition are not tied together, the generated image using options other than those based on iteration count is not "technically" correct. However, I don't think it matters if a pleasing image is generated. I don't believe this disconnect between z and the bailout condition is causing the problem we are seeing. Jonathan
Ah, OK, I think the fog is clearing now. If periodicity checking is on, there will be a problem due to the way the bailout condition is written, right?
Is this something that is documented or is it just a side-effect of the current parser implementation?
In other words, is this problem between periodicity checking and the bailout condition a separate bug?