How to create Affinity Photo psychedelic effect from 1967 ? Create a new document and then go to the paint brush tool. Select anything from the brushes panel such as ink category and then set the color via the color panel to red or green or blue etc and then draw a wave design from top to bottom with the mouse or art pad / pen combination and then go to the brushes panel again and right side menu and bottom entry and new brush from selection' and the current selection will be added to your panel and presets and now you can edit it.
Double click the entry and edit the settings such as decrease spacing and size (most likely it will be too large) and then go to the rotation and rotate it if you wish or keep it as is. Go to the dynamics tab and then go to the hue and saturation at the bottom of the panel and set them to the max. Apply the stroke to check it out and see if you need to change anything such as size jitter or the spacing etc.
Go to the symmetry entry in the control bar and set that to on and set the symmetry to 12 etc and also click the lock check box if you want to keep the symmetry there or have it deselected if you want to move it. I always find that if I don't lock it, I will end up applying the stroke and I will shift the center.
You may wish to re-position it so lock and unlock and lock etc as you wish. Apply the stroke and you will now see 12 brush strokes all equal radiating from the center position. You can repeat this multiple times and fill the entire image with your stroke.
You can also create a new layer and apply the stroke to that try to avoid going over the edge. After you have applied the stroke, you can then move the layer as well as adding effects via the fx in the layers panel. The stroke you create can have effects applied as well, it does not need to be a perfect stroke, it could have 3D effects (remember to rasterize the result with fx turned off) as well as blurs and other strokes applied