Decay

Decay can be a great abstractor producing e.g. rust with beautiful colors and fascinating patterns. But abandoned houses open to weather and forgotten in time you can also offer some interesting abstracts.
Like these walls where the color and plaster eroded and left strange cracks, lines, and blotches.
Found in Kolmanskop, Namibia.

One on One

If you're using a macro lens like the Tamron 90/2.8 VC (F017) you are deep into abstract territory!
We humans are not used to see things up so close. So any shot approaching magnifications of 1:1 ("one on one" ;-) is going to be a bit off the normal scale.
Just captured these orchids in preparation for a shoot-out in my photography club with the topic of ... orchids.
I'd like to capture more of the color than the form of the orchids. So I was looking for a highly abstract rendering of the plant. Not sure that I succeeded though regarding the "highly" part...

Cause and effect

I love this one from a macro-shooting at our local photography club:



Well,  everybody knows that depth-of-field is really slim in macro-shots as it shrinks with the square of the magnification. So some promote focus-stacking to get more dof.
Or you live with it and enjoy the resulting blur from using f5.6 which in this case renders the image in the top-half/background abstract.
Or to be honest: The image was abstract to begin with, as it is simply the artist's palette ;-)

Abstract Nature?

Well, you could always find some pretty abstract images in nature. This one is from a round-trip in Namibia where we visited the famous "Organ Pipes" at Twyfelfontain. The Basalt structures lend themselves easily to some form of abstract photography as they seem to defy the normal expectations of "nature".
I processed every color out of this image except for orange and yellow which already seemed to be the dominant colors in this shot.
Enjoy!