Cool.
Now you can try the varieties. ;)
These can be found in circulation and in many cases this is the only place they can be found.
There is a comprehensive list down the hall; "clad quarter varieties".
1964 Struck on clad planchet (unique)
1965 Rotated reverse
1965 type "b" reverse (if memory serves)
1965 Silver reverse (scarce)
1965
DDO (rare)
1965 Struck on slver planchet (scarce)
1966
DDR 1966 Rotated Reverse
1966 SMS Gouges in 6's (these exist in various degrees but the dramatic ones are pretty tough)
1967
DDO (3 known)(one is very dramatic and quite scarce)
1967
DDR (minor)
1968-D
DDO (dramatic and scarce)
1970-D
DDO (2)(one dramatic and very scarce)
1970-D struck on dime stock (very common but terrible attrition)(~quarter million struck)
1971
DDR (reported to be very rare)
1971-D
DDR1971-D struck on dime stock (much scarcer than the '70-D)
1972-D struck on dime stock
1972-D
DDR (2 known)
1973 (reverse of 1972)(dramatic and scarce)
1974 (reverse of 1972)(rare, probably)
1974 (reverse of 1973)(Very rare since coins under VF are unidentifiable)
1974-D (reverse of 1972)
1976-D
DDO Rare Dramatic
1977 type "d" reverse (scarce, rare in better than VF+)
1977-D type "d" reverse (scarce)(exists in unc)
1978 type "d" reverse (tough, scarce in unc)
1978-D type "d" reverse (scarce, rare in unc)
1979 type "d" reverse (released in N Indiana)(tough, scarce in highgrade)
1979-D type "d" reverse (tough in unc)
1980-P type "d' reverse (tough in unc)
1980-D type "d" reverse (exists in gem)
1981-P type "d" reverse (appears in 1981 mint sets ~.6%)(exists in gem PL)
1981-P
DDO (minor)
1981-D type "d" reverse (found in rolls)
1982-D type "d" reverse (appears in Paul and Judy mint sets et al) (appears PL)
1983-P type "d" reverse (common)(~15%)
1983-D type "d" reverse (very common) (~20%)
1984-P type "d" reverse (distressingly common) (scarce in unc)
1984-D type "d" reverse (distressingly common) (tough in unc)
1984-D/D RPM
1985-P Small Bust
1985-P Rotated Reverse
1989-P Rotated Reverse
1989-D
DDR (minor)
1991-D Struck on half dollar stock.
Time don't fly, it bounds and leaps.