what you ment could be infered based on context, but what you wrote is not what you ment, and assigning definitions to suit your needs doesnt actually qualify as proper use of language. If you wish to actually communicate, use words that mean the same things that you intend them to.
discord - two or more parts that do not exist in harmony. a single object, such as a ticking clock, cannot be discordant, so the statement means nothing. your explanation, if that is truely what you mean to say, would imply that time and our regrets are naturally harmonized, which is a bit of a pessimistic view that still does not benefit your piece.
rust - iron oxide brown, FeO(OH), not the color of your piece.
rubric - iron oxide red, Fe2O3, more commonly known as red ochre or sinoper, also not the color of your piece.
there's no need to defend false definitions in your writing, just say "ooops" and try to avoid using words outside their definitions.
helm's edit has a lot you can take from it, particularly the establishment of planes and focus-depth.