### February 29 – Happy Birthday, Leaplings!

Posted on February 29, 2016

There are probably roughly one-fourth as many leaplings – people who have a February 29th birthday – as there are people with any other specific birthday (such as April 26 or October 10). That's because leaplings are born on Leap Day – February 29 – and there is only one Leap Day per every four or so years.

The reason I say “or so” is because a few “every four years” years are not leap years. The rule is complicated:
• If a year can be even divided by 4, it's a leap year.
• UNLESS it can also be evenly divided by 100, in which case it is not a leap year.
• UNLESS it can also be evenly divided by 400, in which case it is back to being a leap year!

The reason for all these complications is that leap days are added to the calendar so that the calendar keeps time with the Sun. And it takes the Earth 365 days, 5 hours, 48 minutes, and 45 seconds to circle once around the Sun...So instead of giving us a nice clean 365 days a year, or a still-pretty-clean 365.25 days in a year, we have 365.242189 days per year!

You may remember that the year 2000 was a leap year, but the years 1800 and 1900 were not.

ANYWAY...

Four years ago I wrote about Leap Day, and here we finally are again. This time, I thought I would celebrate a few people born on this rarest of days...

Vance Haynes, Jr. is an archeologist and a geologist. He revolutionized his field, which is geoarchaeology – also known as archaeological geology. He helped figure out the timeline of human migration into and through North America, and he helped maintain scientific access to important human skeletal remains.

Even though he was born on this day way back in 1928, Haynes is still active in the School of Anthropology at the University of Arizona! (He turns 88 today – hooray!)

Seymour Papert is a mathematician, a computer scientist, and an educator. He is one of the pioneers of A.I. (artificial intelligence), and best of all, he and a co-inventor created the Logo programming language.

Logo is a programming language that helps kids learn how to program. Papert created a small robot called the Logo Turtle. Kids could give it a list of movements to make – including “Pen up” and “Pen down,” and they could use the turtle to draw designs.

And not just simple designs, either! Using Logo is a great way to learn about recursion. It is recursion that makes fractals possible!

 Recursion is when you repeatedly call on a routine.In the example above, all the turtle is doing is drawingboxes. But in between each box, the turtle just turns a littlebit so that the next box is slightly offset from the last.And when you do that over and over and over again, theresult is surprisingly pretty!The example below is a different routine that is called onover and over - with a different, even more complex, result.

Like Haynes, Papert was born on this date in 1928. He was born in South Africa,
got his PhD in England, and has lived in the U.S. since 1963.

Tim Powers is a science fiction writer (like me! – but way more successful!). He was born in Buffalo, NY (near where my husband was born!) and now lives in San Bernardino County, Southern California (like my husband and me!), and he sometimes teaches in the Orange County High School of the Arts and Chapman University (my daughter's alma mater!).

Powers and a few of his pals started the steampunk literary movement (which has spilled out into fashion and design and style). Steampunk is a kind of alternative history fiction in which steam power remains the most important form of energy. Steampunk is generally inspired by Victorian times.

Powers was born on this date in 1952.