# Fmx - newbie question about proto

**URL:** <https://forum.kirupa.com/t/fmx-newbie-question-about-proto/93667>\
**Category:** Uncategorized\
**Created:** [November 3, 2003, 5:01pm UTC](https://forum.kirupa.com/t/fmx-newbie-question-about-proto/93667 "2003-11-03T17:01:29Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![aquaman](https://avatars.discourse-cdn.com/v4/letter/a/a587f6/32.png) [@aquaman](https://forum.kirupa.com/u/aquaman)\
**Post date:** [November 3, 2003, 5:01pm UTC](https://forum.kirupa.com/t/fmx-newbie-question-about-proto/93667/1 "2003-11-03T17:01:29Z")

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Hi I found this the equation in the attach file, I have questions about it, I understand what is x,y,d,and calBackFunc, but what about callBackObj and param.

Please can someone help me

thanks