A fenced code block:

    }
    enoN = ]tnI[noitpO :dleif lav
    { )gnirtS :eman(elpmaxE ssalc

And another one, this time with an empty line:

    eurt // ;)(ytriDsi.durc.atad
    ;)1(retnuoc.atad
    eslaf // ;)(ytriDsi.durc.atad
    ;)ledom ,}{(esu.cnys.ok = atad rav

    ;)}
    }0 :retnuoc{ :sdleif
    ,elbat :elbaTatad
    ,erots :erotSatad
    {(ledoM.cnys.ok = ledom rav

and here is another one:

    }
    ;)smarap ,"" ,yek ,ELDNUB(tluafeDrOegassem.eldnuBnommoC nruter
    { )smarap ...tcejbO ,yek gnirtS )EMAN_ELDNUB = eldnuBecruoser(yeKytreporP@(knalBrOegassem gnirtS citats cilbup

    }
    ;)smarap ,yek ,ELDNUB(egassem.eldnuBnommoC nruter
    { )smarap ...tcejbO ,yek gnirtS )EMAN_ELDNUB = eldnuBecruoser(yeKytreporP@(egassem gnirtS citats cilbup

test opening with more than 3 ticks

    decnef eb llits dluohs
    `````
    decnef eb llits dluohs
    ```
    }
    ;)smarap ,"" ,yek ,ELDNUB(tluafeDrOegassem.eldnuBnommoC nruter
    { )smarap ...tcejbO ,yek gnirtS )EMAN_ELDNUB = eldnuBecruoser(yeKytreporP@(knalBrOegassem gnirtS citats cilbup

    }
    ;)smarap ,yek ,ELDNUB(egassem.eldnuBnommoC nruter
    { )smarap ...tcejbO ,yek gnirtS )EMAN_ELDNUB = eldnuBecruoser(yeKytreporP@(egassem gnirtS citats cilbup