one assumption i made is the symbol is a diverging lens[img][/img]

if this assumption is valid, then
maybe u can explore this
and find out yourself.

picture 1 seems possible, u know where? appears to me to be at F on the right [img];topic=2312.0;attach=4492;image[/img]

pictue 2 seems to require the object to be an infinity on the right side

picture 3 i cant get it, is it a trick question?