True mirror effect?

Hi, all.
I may be having a bad day today
, but I can't figure out how to make a plain true mirror effect i.e. make a material reflect the environment in real time.
Maybe wz4 just can't do that, but damn... this is interesting! Any ideas?
Thank you.
I may be having a bad day today

Maybe wz4 just can't do that, but damn... this is interesting! Any ideas?
Thank you.