KUALA LUMPUR: Try writing the date today, and you will see a string of twos' arranged in neat fashion: 22-2-22.
But, you'll have to live for another 100 years more to see this date sequence again at 22-2-2122, and 100 more to see the real 22-2-2222!
In fact, Feb 22 this year is also a full eight-digit palindrome date in the British date format (day-month-year) at 22-02-2022.
A palindrome date is a date number that reads the same forward and backwards.
According to Professor Aziz Inan, today's date is also a "ubiquitous palindrome date" since its short-hand version is a palindrome, irrespective of the date system used to express it.
In the British date format, the short-hand for today's date is 22-2-22, while in the United States version, it is 2-22-22. Either way, the date appears the same, forward and backwards.
Inan, 66, and an electrical engineering professor at the University of Portland, said this year contained two ubiquitous palindrome dates and both occurred this month on Feb 2 and 22.
However, the Turkish-born academician, who studies palindrome dates as a hobby, noted that the Feb 22 date was rarer compared with Feb 2 for two reasons.
"First, ubiquitous palindrome dates like Feb 2, 2022 (2-2-22) occur every 11 years, with the next one being March 3, 2033 (3-3-33) and subsequently, April 4, 2044 (4-4-44), and more will follow until the end of the century.
"However, palindrome dates like Feb 22, 2022 (22-2-22) will never appear again in this century because the number of days in a month cannot exceed 31 (There is no such thing as a calendar date of 33-3-33).
"You have to wait for the next century to see the 22-2-22 sequence again on Feb 22, 2122.
"Secondly, Feb 22, 2022 is also a full eight-digit palindrome date (22-02-2022) and there will be a seven-digit palindrome date again after 200 years on Feb 22, 2222 (22-2-2222)," he told the New Straits Times.
Inan pointed out that full eight-digit palindrome dates were extremely rare and no such dates occurred between the 15th and 20th centuries.
Based on the day-month-year date format, Inan said, the 21st century contained 29 full eight-digit palindrome dates, and all of them will fall in February.
The symmetry of palindrome dates, he said, was the secret why February was considered the "miracle month".
"The year number in this century starts with '20' and the reverse of that yields 02', which corresponds to the month of February. So, all full eight-digit palindrome dates naturally must occur in February," he said.
Inan's fascination for palindrome dates began about a decade ago, when he was scouting for numbers with special properties to develop math puzzles.
His chance discovery of symmetrical numbers, like 2002, led him to realise that such numbers could also occur as dates.
The professor had celebrated every palindrome day ever since.
This year, Inan made a paper bag hat, with Feb 2 and Feb 22 written on it, to mark the two ubiquitous palindrome dates. He wore the hat throughout the day on Feb 2 and planned to do the same today.
Besides the two ubiquitous palindrome dates, Inan said, this year also featured several other palindrome days, depending on the date format and number of digits used.
Based on the US date format with five digits, all 10 palindrome days for 2022 would occur this month, including eight consecutive days between Feb 20 and Feb 28.
The eight consecutive five -digit palindrome days are 2-20-22; 2-21-22; 2-22-22; 2-23-22; 2-24-22; 2-25-22; 2-26-22; 2-27-22; and 2-28-22. Note that one of these, Feb 20 is also a full seven-digit palindrome day at 2-20-2022.
Meanwhile, the British date format offered 11 five-digit palindrome dates (including Feb 2), that occurred on the 22nd of every month this year except October and December.
Indeed, the two full palindrome dates this year, Feb 20 (in the US date format as 2-20-2022) and Feb 22 (in the British date format as 22-02-2022), are just two days apart.