Happy Independence Day.
These are from my small collection of US stamps.
These coil stamps were still printed with engraved plates. Nowadays the vast majority of American-issued postage stamps are printed by using offset-lithography.
Coil stamp Issued Dec.17, 1981
Perf. 10 vert. |Engraved |No Watermark
1895 A1281 20c Black, dark blue and red
Flag Over Capitol Dome
Coil stamp Issued Mar.29, 1985
Perf. 10 vert. |Engraved |No Watermark
2115 A1498 22c Blue, red and black
Flag Over Mt. Rushmore
Coil stamp Issued Mar.29, 1991
Perf. 10 vert. |Engraved |No Watermark
2523 A1878 29c Blue, red and claret
[Source: Scott 2003 Standard Postage Stamp Catalogue, Vol. 1]