I’m useless at mathematics but it seems to me that any co-ordinates (two or more) that appear in a reflection or shadow have the original properties x,y inverted, (x,y)-z where z is the mirror image (minus or negative) plus another variable lets say (dv) to account for distortions introduced by the method of reflection in relation to the original. Plus another variable for all the distortions introduced from your viewing point back to the original (dz). This can include angular for say shadows (az), which are a sort of reflection, or logarithmic for size distortions (lz), or momentum for time distortions (tz) and I suspect that the mathematical formula which must be expressed as three objects where two must be known so as to calculate this from any perspective is horrendously complicated.
Attempting the same through a perfect mirror or substance with only one reflection does not produce any worthwhile answers.
Now you know why I’m useless at maths, I only understand the logic of a dartboard as viewed through a reflection in the bar overhead mirror.
Cheers