//for each available symbol..
for (int i = 0; i < availableSymbols.size(); i++) {
Symbol symbol = availableSymbols.get(i);
SymbolButton button = new SymbolButton(symbol);
button.addActionListener(this);
buttonList.add(button);
c.gridx = col;
c.gridy = row;
panel.add(button, c);