# Definition of an exercise ruler & compass.
# syntax of the file.
# points:  each line defines a point.  x,y
# lines:   each line defines two points on a line.   x1,y1,x2,y2,type
#          type: 1 (segment), 2 (line), 3 (semiline direct), 4 (semiline inverse)
#	   type is facultative, defaulting to 1.
# circles: each line defines a circle. x,y,r,n
#	   where (x,y) is the center, r=radius,
#          n is the number of point for the center (if n>0).
# goal: each line defines an object. First item is the type of the object
# (point,line or circle), the rest are parameters (same as above).
# goal_text: text explaining the goal. (language-dependent)

title=ȷ߶
boundary=circles
theta=!random 0,2*pi
points=cos($theta),sin($theta)\
-cos($theta),-sin($theta)
lines=-cos($theta),-sin($theta),cos($theta),sin($theta),1

goal=point,cos($theta)/3,sin($theta)/3\
point,-cos($theta)/3,-sin($theta)/3
goal_text=߶ 1-2 һΪ
hint=һֱƽ֪߶. Ȼֱϱ 4 Ⱦĵ.\
, Ե 1, 2 Ϊ˵㽫ֱϵ 4 Ͷ䵽֪߶.
solution=circle,1,2\
circle,2,1\
point,circle,1,circle,2\
hide,point,4\
circle,3,1\
point,circle,1,circle,3\
line,3,5#Line 2 is parallel to line 1.\
point,line,2,circle,2\
hide,circle,1\
hide,circle,2\
hide,circle,3\
circle,5,3\
point,line,2,circle,4#Points 7,5,3,6 are at regular intervals, hence 3 and 5 divide 6-7 by 3.\
hide,circle,4\
line,1,7\
line,2,6\
point,line,3,line,4#Point 8 will be the base of the projection.\
line,8,5\
point,line,1,line,5\
line,8,3\
point,line,1,line,6

