Pseudo code solution for the 9 ball problem

9ball.js

// Divide balls a - i into THREE groups. 
// Use two of them to weigh on the scales, ignore the third
if (abc < ghi) {
    // a, b or c must be lighter
    // Take any two of these to compare, ignore the third
    if ( a < c ) {
        console.log("a is lighter");
    } else if ( a == c ) {
        console.log("b is lighter");
    } else {
        console.log("c is lighter");
    }
} else if (abc == ghi) {
    // d, e or f must be lighter
    // Take any two of these to compare, ignore the third
    if ( d < f ) {
        console.log("d is lighter");
    } else if ( a == c ) {
        console.log("e is lighter");
    } else {
        console.log("f is lighter");
    }
} else {
    // g, h or i must be lighter
    // Take any two of these to compare, ignore the third
    if ( g < i ) {
        console.log("g is lighter");
    } else if ( a == c ) {
        console.log("h is lighter");
    } else {
        console.log("i is lighter");
    }
}