Step 1: 14 Calendars
The graphic is a table from a web page that tells the user which basic calendar applies to any year in the 1900s and in the 2000s (20th and 21st Centuries). Click on this link to go to that web page in order to see this table in a more legible form. A table like this also appears in the calendar section of various almanacs. You can find an almanac in most libraries.
If you consult the table, the calendar for the year 2011 is followed by the numeral 6. Look for other occurrences of the code numeral 6. The calendar for 2011 will be repeated again during the 21st Century in 2022, 2033, 2039, 2050, 2061, 2067, 2078, 2089, and 2095. During my lifetime it was also the pattern calendar for 2005, 1994, 1983, 1977, 1966, 1955, and 1949. (I was born in 1946.)
Step 2: Back to 1990, Forward to 2018
This calendar was printed in Germany. Like many other countries, some things are different. First, the German word for "July" is "Juli." Second, the week on many calendars begins with Monday and runs through Sunday, rather than beginning with Sunday and running through Saturday. Third, the abbreviations for the days of the week are different because the names of the days in German are different. I do have one calendar from Germany that prints the names of the days above one another in five or six languages, including English.
You can have some fun directing a friend to a calendar on your wall that is obviously the wrong year, and yet, the dates are correct. And, you can enjoy an old calendar with a favorite theme or favorite pictures yet one more time.