Creating overlapping "arrow" stimuli

Coding
1

Hi all,

I am new to coding in psychopy and am trying to code a stimulus that consists of two overlapping (in opposite directions; see attached figure) “>” “<” arrows in which half of one arrow is “on top” of the other, while the other half is “below” the other arrow. Is this possible in psychopy? Alternatively I could create the image like the one I’ve attached, but one reason for wanting to do it in psychopy is to take advantage of the isoluminance capability of psychopy.

Thanks in advance!
Lee

blgr_only

2

I think you’d need to do it with four lines, not two arrows.

2 Likes
3

Yes, its all about the drawing order. Things drawn later get drawn on top of things drawn before them. So as Wakefield suggests, in this case, have four separate lines and draw them in this order:

  • upper blue
  • upper green
  • lower green
  • lower blue

and alter the order as required to get other forms of overlap.

1 Like
4

hello,

thank you both wakecarter and Michael! I’ll do this.

Best,
Lee