alzheimer_test: no visible global function definition for 'formatUL'
alzheimer_test: no visible global function definition for 'menu'
alzheimer_test: no visible global function definition for
  'flush.console'
gomoku: no visible global function definition for 'par'
gomoku: no visible global function definition for 'plot'
gomoku: no visible global function definition for 'segments'
gomoku: no visible global function definition for 'points'
gomoku: no visible global function definition for 'box'
gomoku: no visible global function definition for 'locator'
lights_out : replot: no visible global function definition for
  'symbols'
lights_out: no visible global function definition for 'par'
lights_out: no visible global function definition for 'plot'
lights_out : mousedown: no visible global function definition for
  'grconvertX'
lights_out : mousedown: no visible global function definition for
  'grconvertY'
lights_out: no visible global function definition for
  'getGraphicsEvent'
mine_sweeper: no visible global function definition for 'par'
mine_sweeper: no visible global function definition for 'plot'
mine_sweeper: no visible global function definition for 'symbols'
mine_sweeper : plot.mine: no visible global function definition for
  'symbols'
mine_sweeper : plot.mine: no visible global function definition for
  'segments'
mine_sweeper : plot.flag: no visible global function definition for
  'symbols'
mine_sweeper : plot.flag: no visible global function definition for
  'segments'
mine_sweeper : mousedown: no visible global function definition for
  'grconvertX'
mine_sweeper : mousedown: no visible global function definition for
  'grconvertY'
mine_sweeper : mousedown: no visible global function definition for
  'text'
mine_sweeper : mousedown: no visible global function definition for
  'symbols'
mine_sweeper: no visible global function definition for
  'getGraphicsEvent'
sliding_puzzle : replot: no visible global function definition for
  'par'
sliding_puzzle : replot: no visible global function definition for
  'plot'
sliding_puzzle : replot: no visible global function definition for
  'segments'
sliding_puzzle : replot: no visible global function definition for
  'symbols'
sliding_puzzle : replot: no visible global function definition for
  'text'
sliding_puzzle : mousedown: no visible global function definition for
  'grconvertX'
sliding_puzzle : mousedown: no visible global function definition for
  'grconvertY'
sliding_puzzle: no visible global function definition for
  'getGraphicsEvent'
tag_cloud: no visible global function definition for 'URLencode'
tag_cloud: no visible global function definition for 'download.file'
tower_of_hanoi: no visible global function definition for 'rainbow'
tower_of_hanoi: no visible global function definition for 'par'
tower_of_hanoi : draw.hanoi: no visible global function definition for
  'plot'
tower_of_hanoi : draw.hanoi: no visible global function definition for
  'rect'
tower_of_hanoi : draw.hanoi: no visible global function definition for
  'barplot'
Undefined global functions or variables:
  URLencode barplot box download.file flush.console formatUL
  getGraphicsEvent grconvertX grconvertY locator menu par plot points
  rainbow rect segments symbols text
Consider adding
  importFrom("grDevices", "getGraphicsEvent", "rainbow")
  importFrom("graphics", "barplot", "box", "grconvertX", "grconvertY",
             "locator", "par", "plot", "points", "rect", "segments",
             "symbols", "text")
  importFrom("utils", "URLencode", "download.file", "flush.console",
             "formatUL", "menu")
to your NAMESPACE file.