Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at com.yarcat.chemistrylines.game.FormulaLinesGame$FormulaTerminalGenerator.fill(FormulaLinesGame.java:65)
at com.yarcat.chemistrylines.game.ElementGenerator.preview(ElementGenerator.java:28)
at com.yarcat.chemistrylines.game.LinesGame.previewNextElements(LinesGame.java:69)
at com.yarcat.chemistrylines.swing.SwingChemistryLines.refreshPreview(SwingChemistryLines.java:136)
at com.yarcat.chemistrylines.swing.SwingChemistryLines.refresh(SwingChemistryLines.java:132)
at com.yarcat.chemistrylines.swing.SwingChemistryLines.tryMakeMove(SwingChemistryLines.java:205)
at com.yarcat.chemistrylines.swing.SwingChemistryLines.mousePressed(SwingChemistryLines.java:186)
at java.awt.Component.processMouseEvent(Component.java:6379)
...