Things that require the passing of time to exist

Music

http://www.hark.com/clips/fmkkwlptfd-harmonica-riff-10

Echo

http://www.hark.com/clips/jcyzpxnclr-thundersharpattac-pe1009402

Things available to human touch

Ball

Apple

Something defined by its relationship to other things

Mother/Child

Perfect Fourth

http://en.wikipedia.org/wiki/File:Fourth_ET.ogg

Representations

Painting

Synthetic Voice

http://www.hark.com/clips/plgvgdtsql-musical-element-synth-voice-do-stab-production-element-imaging-element-accent-transition

Of imagination

Mermaid

Alien Gun Shot

http://www.hark.com/clips/bhvrzvtqgp-alien-gun-shot