First, RNA does not have T (thymine) bases, it uses U (uracil).
Second, the bases between 3' and 5' have to come in threes; the game only admits [ACGT]*, not [ACGT]{3}* (never mind [ACGU]{3}*).
Third, it treats any form of the latter, constructed purely via its block stacking, as a syntax error, which should be impossible to construct that way.
First, RNA does not have T (thymine) bases, it uses U (uracil).
Second, the bases between 3' and 5' have to come in threes; the game only admits [ACGT]*, not [ACGT]{3}* (never mind [ACGU]{3}*).
Third, it treats any form of the latter, constructed purely via its block stacking, as a syntax error, which should be impossible to construct that way.