The cardinality of the two intervals [0,1] and [0,2] are equivalent. E.g. for every number in the former you could map it to a unique number in the latter and vice versa. (Multiply or divide by two)
However in statistics, if you have a continuous variable with a uniform distribution on the interval [0, 2] and you want to know what the chances are of that value being between [0,1] then you do what you normally would for a discrete set and divide 1 by 2 because there are twice as many elements in the total than there are in half the range.
In other words, for weird theoretical math the amount of numbers in the reals is equivalent to the amount of any elements in a subset of the reals, but other than those weird cases, you should treat it as though they are different sizes.
You just brought back memories of my siblings and I walking around outside barefoot to the point these things penetrated our shoes more easily than our feet.
In rural southern Utah these things are literally everywhere. If you go out with cheap foam flip-flops, the entire bottom of the shoe will embedded with dozens of these seconds after you start walking around lol
Kind of oddly satisfying to pull them out of the soles of shoes tbf