The main example of figurative language in Neil Young’s lyrics to Sugar Mountain is the oft-repeated refrain that open and closes the song, and occurs following each stanza suggesting an alienated youth striving to break free of the bonds that hold him tight:

Oh, to live on Sugar Mountain

With the barkers and the colored balloons,

You can’t be twenty on Sugar Mountain

Though you’re thinking that

you’re leaving there too soon,

You’re leaving there too soon.

 The stanzas in Young’s song that describe a young, probably rebellious male (The line “There’s a girl down the aisle/Oh, to turn and see her smile” suggests that the central figure is a male attracted to this female) anxious to remove himself from his current existence (“No you say you’re leavin’ home/’Cause you want to be alone.  Ain’t it funny how you feel/When you’re findin’ out it’s real?”), but finding that independence is not always all it’s cracked up to be, is fairly straightforward story-telling.  It is that above quoted refrain, however, that presents Young’s use of figurative language.  That refrain can be categorized as a “symbolic” form of figurative language.  “Sugar Mountain” represents or symbolizes lost youth.  The references to “barkers and the colored balloons” suggests a carnival or state or county fair, with midways and games of chance colorfully decorated and fronted by lower-echelon forms of humanity.  “Sugar Mountain” represents the fairy-tale existence that adults look back upon with nostalgia for a simpler time, when the responsibilities of adulthood didn’t yet exist. 

Joni Mitchell’s The Circle Game is full of examples of figurative speech, but examples of allusions are a little harder to find.  Considered sort of a sister-song to Young’s Sugar Mountain, The Circle Game similarly laments the passing of youth and lost innocence.  Unlike Young’s lyrics, though, Mitchell’s truly captures the innocence of youth – in this case, the baby given up for adoption following a too-young for responsibility pregnancy and whom she consequently missed watching grow up.  Mitchell’s lyrics are much more poignant, in that they reference the complete innocence of childhood, and the speed at which the years flow by:

Yesterday a child came out to wonder
Caught a dragonfly inside a jar
Fearful when the sky was full of thunder
And tearful at the falling of a star
Then the child moved ten times round the seasons
Skated over ten clear frozen streams

As with Young’s figure, Mitchell’s turns 20, and is forced to acknowledge that the carefree days of youth are gone, and they’re not coming back.  We can do is remember the past, but we can’t bring it back:

We can't return we can only look behind

From where we came

Literary allusions are usually fairly straightforward references to people, events, locations, etc.  The Circle Game does not have any blatant examples of allusions, other than to Sugar Mountain (Mitchell:“So the years spin by and now the boy is twenty”; Young: “You can’t be twenty on Sugar Mountain”).  Mitchell’s reference, however to “the carousel of time” can be considered an allusion to the “circle of life,” in which life moves constantly forward, and there’s no reversing that tide.  This is more an example of figurative speech, however, than an allusion.  The main allusion in The Circle Game is to Neil Young.