17thcentury 18thcentury activityprograms art cartoonsandcomics comicbooks educationalaspects engineering enlightenment etc exercises experiments history inventions juvenileliterature light mathematicalrecreations mathematics medicineinthearts miscellanea modern motives opticalillusions problems science sciencemuseums scienceprojects scientificliterature strips studyandteaching themes visualperception wz330s779a1994