# Shifting a stimulus and correct phase/cycle value

**URL:** <https://discourse.psychopy.org/t/shifting-a-stimulus-and-correct-phase-cycle-value/9223>\
**Category:** Coding\
**Created:** [September 28, 2019, 11:18am UTC](https://discourse.psychopy.org/t/shifting-a-stimulus-and-correct-phase-cycle-value/9223 "2019-09-28T11:18:51Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![mnyman](https://avatars.discourse-cdn.com/v4/letter/m/d26b3c/32.png) [@mnyman](https://discourse.psychopy.org/u/mnyman)\
**Post date:** [September 28, 2019, 11:18am UTC](https://discourse.psychopy.org/t/shifting-a-stimulus-and-correct-phase-cycle-value/9223/1 "2019-09-28T11:18:51Z")

</div>

Hi all.  
I just recently discovered Psychopy and being studying it since then, so accept my apologies if these doubts are answered elsewhere.  
I’ve found information on the forum describing 1 phase = 1 cycle and in the documents quoting:

> “A phase of 0.25 will cause the image to shift by half a cycle…”

Wich one would be correct?  
Is it possible to drift the stimulus in a direction on a constant **“units”** per second basis using _phase_ when dealing with a GratingStim (e.g. 10deg/s to the right)?  
Thanks in advance.