%开始！
clear all
screens=0;
[wPtr,rect]=Screen('OpenWindow',screens,0,[]);
HideCursor
black=BlackIndex(wPtr);
white=WhiteIndex(wPtr);

flipSpd=13;
b=Screen('Flip',wPtr); %=vbl
c=Screen('GetFlipInterval',wPtr);%=monitorFlipInterval

Screen('FillRect',wPtr,black);
b=Screen('Flip',wPtr);
for i=1:10
Screen('FillRect',wPtr,[0 177 177],[100 150 200 250]);
Screen('DrawLine',wPtr,[0 177 177],1,2,3,4,5);%从（1，2）到（3，4），5是线宽
Screen('FillOval',wPtr,[0 177 177],[]);
Screen('Textsize',wPtr,150);
Screen('DrawText',wPtr,'NMD',200,20,[0 0 255]);
b=Screen('Flip',wPtr,b+(flipSpd+c);
end