Decimal Points in unary

Question

This questions asks how to write 0 in unary and the answer given was (literally) as nothing (with no symbol). I'm wondering how you would write a decimal (0.1 for example) in unary. Since 1^(-n) = 1, I presume it's impossible, $$.x = x,$$ $$.xx = xx$$ and so on. Is there a way to write numbers with decimal places in unary?