If only there were an easy way to do grouping with parentheses in natural language...
x = year is divisible by 4
y = year is divisible by 100
z = year is divisible by 400
Year is a leap year = ( x && !y | | ( x && ( y && z ) ) )
A better way to term the requirement in natural language is : "A year is a leap year if it divisible by 4. If a year that is divisible by 4 is also divisible by 100, it is not a leap year. However, if a year is divisible by 4, 100,
and 400, then it it a leap year."
By this assertion 2000 was a leap year...
HTH,
-Nate