             fetchImage(url) { [unowned self] image in
                 let lgtm = Lgtm(url: url, image:image)
                 self.favStack.enqueue(lgtm)
-                if self.favStack.count >= self.stackLimit {
+                if self.favStack.count >= self.StackLimit {
                     self.fetchingRealm = false
                 }
             }

    /// fetch from lgtm.in/g to limit
    private func fetchLgtmFromServer() {
        fetchFromServer { [unowned self] in
            if self.stack.count < self.stackLimit {
                // fetch until stack.count reaches to limit
                self.fetchLgtmFromServer()
            } else {

    private func popRandomLgtm() -> Lgtm? {
        let lgtm = stack.dequeue()
        if let lgtm = lgtm {
            if history.count >= HistoryLimit {
                history.dequeue()
            }
            history.enqueue(lgtm.url)
