rule OfExample2
{
    strings:
        $foo1 = "foo1"
        $foo2 = "foo2"
        $foo3 = "foo3"

    condition:
        2 of ($foo*)  // equivalent to 2 of ($foo1,$foo2,$foo3)
}

rule OfExample3
{
    strings:
        $foo1 = "foo1"
        $foo2 = "foo2"

        $bar1 = "bar1"
        $bar2 = "bar2"

    condition:
        3 of ($foo*,$bar1,$bar2)
}