 On a long piece of paper about ( outseam + ( (4 " or 10.4 cm) ) ) long and ( seat + ( (6 " or 15.6 cm) ) ) wide, draw a line down the middle. Near the top, select a point and mark point 0 . From 0 down to 1 is ( outseam  ( (1 " or 2.6 cm) ) ) . From 1 up measure up inseam to 2 . 3 is midway between 1 and 2 ( ( inseam / 2 ) ). 4 from 3 is 2 " (5.2 cm) . Square out from points 0 , 2 , 4 , and 1 . 5 from 2 is ( seat / 5.5 ) . 6 from 2 is ( seat / 12 ) 7 from 2 is ( seat / 12 ) Square up from 6 to locate 8 on line 0 Square out from 7 to locate 9 on line 6 10 from 9 is 0.25 " (0.6 cm) Draw line 8  10 . 11 from 10 is ( seat / 4 ) 12 from 8 is ( ( waist / 4 ) + ( (0.5 " or 1.3 cm) ) ) 13 and 14 from 4 is ( knee_width / 2 ) 15 and 16 from 1 is ( cuff_width / 2 ) 17 from 1 is ( cuff_depth ? ( ( 3 * cuff_depth )  ( (0.25 " or 0.6 cm) ) ) : ( (2 " or 5.2 cm) ) ) (allowance for the cuff (if any) is included in this measurement). Square out from 17 . The waist line form 8 is squared by line 8  10 until it is about 0.25 " (0.6 cm) below line 8  12 . Then it curves gently into 12 . The fly fall (front rise) follows the straight line 8  10 and then makes a shallow curve into 5 . Through 11 the outseam is vertical from about 1 " (2.6 cm) above to 0.5 " (1.3 cm) below. Continue upward, curving into 12 . Shape the leg, making the inseam and outseam vertical from the bottom to at least 2 " (5.2 cm) above 15 and 16 and identical to each other from the bottom to the knee. Above the knee the inseam is a natural continuation, waiting until almost the top to curve into 5 . The outseam also continues naturally above 14 , easing outward to meet the continuation downward from 11 . Add notches (for assembly) at the following points:

 The pattern back guide is used to determine the slope of the back pattern piece. Draw horizontal lines 0 , 7 , and 2 the same distance apart as on the pattern front. Near the right on line 2 mark point A . B from A is ( ( seat / 4 ) + ( (2 " or 5.2 cm) ) ) Square up from A and B to locate C and D on line 0 . E from B is ( ( waist / 4 ) + ( (1.5 " or 3.9 cm) ) ) The distance between E and A should be ( diff = ( ( ( seat / 4 ) + ( (2 " or 5.2 cm) ) )  ( ( waist / 4 ) + ( (1.5 " or 3.9 cm) ) ) ) ) F from C is ( diff / 2 ) G from D is ( diff / 2 ) Draw line A  F and locate point X where it crosses the horizontal line 7 . H from F is 4.5 " (11.7 cm) From H square down 2.5 " (6.5 cm) to locate J . K and L are each 1/4 " (0.6 cm) from H . Draw lines J  K and J  L (back dart). Draw line B  G and extend it 1/8 " (0.3 cm) to M . From M square out to 1/8 " (0.3 cm) below the horizontal line 0 ; then curve gradually into K . From L to F draw a curve that dips 1/8 " (0.3 cm) below the straight line. Extend the straight lines M  B and F  A to several inches below line A  B , and cut out the pattern back guide along the curved lines M  K and L  F . Cut out the vee for the back dart, all the way to J . 
 For the back pattern, use a piece of paper about ( outseam + ( (12 " or 31.2 cm) ) ) long and ( seat + ( (12 " or 31.2 cm) ) ) wide, draw a line down the middle. Lay the front pattern piece on the paper, lining up the 0  1 line of the front with the line on the paper, and draw around it. Indicate notches and points 10 and 11 . Take away the front piece and label points 5 , 13 , 14 , 15 , and 16 . Draw line 10  11 and extend it to the right. 18 from 11 is 2 " (5.2 cm) Place point X on the pattern back guide on point 18 on the paper. Using the common point as a pivot, swing the guide up until side M  B touches point 10 on the paper. Draw around the guide above 10 and 18 ( X ). Label M and F . 19 and 20 are 1/2 " (1.3 cm) from 13 and 14 . 21 and 22 are 1/2 " (1.3 cm) from 15 and 16 . 23 from 5 is ( ( seat / 24 ) + ( (3/8 " or 1 cm) ) ) , that is, half of the distance from 7 to 2 plus 3/8 " (1 cm) . 23 from 19 is the same as 5 from 13 . The seat seam (back rise) follows the straight line M  10 , becomes a shallow curve just outside the 10  5 curve of the front, and runs through 5 into 23 , finishing up straight for about the last 1 " (2.6 cm) . From the bottom to the knee the inseam lies 1/2 " (1.3 cm) outside the front outline. Above the knee it continues naturally, doing most of its curving into 23 near the top. The outseam too is 1/2 " (1.3 cm) outside the front outline from the bottom to just above the knee. Then it eases outward to pass through 18 and curve just outside the F  18 line into F . The bottom is in line with that of the front. Cut out the pattern back, and cut knee and bottom notches. 